Your Starting items normally, would be the 2 following choices:
This choice improves your clearing speed by increasing the damage you deal by a percentage to monsters, as well as adding in bonus true damage against monsters.
This option supplies you with additional defense, allowing you to take less damage. However, you do suffer a drop in clearing speed by taking this item.
Whichever option you start with is fine, but keep in mind you will usually build cloth armor into another item, while the machete you will generally sell.
On your first return trip, you will need to pick up boots to improve your movement speed. After which spend money on a long sword(if you returned with enough). The long sword purchase is to set you on the path of buying either phage, Vampiric Scepter, or Brutalizer. Which item you build into depends on your situation.
if you find that you need the HP,and have trouble keeping up with enemies, Phage should be first.
If you find that you need sustain, then pick up Vampiric scepter.
If you need damage, then brutalizer is the obvious choice.
Either way, you will generally buy 3 long swords(at least) every game for these three items. If you can do so on the first back, buy 2 long swords, but only if it does not hinder your ability to pick up boots on the first trip back.
Why are these 3 items core items?
These three are core because of the powerful items they build into later on. Brutalizer you will always build into a Black cleaver. The armor penetration, cdr, health and bonus attack damage are all very useful, and too good to pass up, especially on a Bruiser like Vi. Vampiric scepter holds several build paths, 3 of which are good enough to be worthy of building(Bloodthrister, Ravenous Hydra, Hextect Gunblade). Phage builds into 2 items that work well for Vi, Frozen mallet, and trinity force, both of which are great choices.
Because of the options these 3 items represent later on, they are important enough to be counted as the core items of the build, and should generally be bought every game.
Make sure that you you do return to buy the items you need, but not so often that it causes you to lose out on experience(which in turn can cause you to lose out on gold, delaying your finalized items). Do make sure that while you are completing your core items, that you think ahead enough to decide which items you want to finish them into. Your ending item purchases should reflect not just a need to damage, or health, but what you need for that specific game.
+250 health +20 armor +20 magic resistance Unique â€“ Legion: Nearby allied champions gain +10 armor, +15 magic resist, and +10 health regen per 5 seconds.
This item will provide you with round the board defense, increasing your health, armor, and MR, as well as buffing your teammates that are nearby as well. This item is a perfect for a brusier because of the defensive stats it provides, allowing that bruiser to have some fair protection in the mid game. However, moving into late game, this item isn't going to fair as well in it's defensive capabilities, meaning you will need to upgrade it.
+400 health +20 armor +30 magic resist Unique - Legion: Nearby allies gain 10 armor, 30 magic resist and 10 health regen.
Upgraded form Aegis, this item brings late game standing to the item. Increasing the health and MR provided, but sadly neglecting Armor. However, despite it's neglecting to improve its Armor, It is still granting a total of 400 health, 30 armor, and 60 MR to the carrier, as well as still providing stat boosts to the rest of the team, which is nothing to shabby. Pairing this with a Guardian angel will give her some great tanking ability, granting her the ability to effectively initiate, dish out large damage, and possibly escape, or at least stick around much longer to sacrifice herself while her team mops up.
+250 health +50 attack damage +10% cooldown reduction Unique passive +10 armor penetration Dealing physical damage to an enemy champion reduces their armor by 6.25% for 4 seconds. This effect stacks up to 4 times.
The new version of black cleaver is so much better then before. Dropping it's AS boost was a great idea, as it traded that out for a much better passive. While granting AD, Health, CDR, and flat armor pen, its passive allows it to shred armor even further. Before, it's passive would shred by only using auto attacks and as a flat amount instead of as a percentage. Now this Item shreds armor whenever you strike an enemy with any physical damage source, making this item great for AA based champs, and AD casters alike.
+70 Attack Damage +12% Life Steal Passive: Gains 1 stack per kill, up to a maximum of 30. Each stack grants +1 Attack Damage and +0.2% Life Steal (max: +30 Attack Damage and +6% Life Steal). Half of the current stacks are lost upon death.
It's a great choice whether you're wanting to snow ball into late game or not. It provides a great boost to not only your attack damage, but it gives a hefty amount of life steal. With it's rework, it presents a much stronger starting presence then it used to, and having that 10 bonus ad transferred to being static AD makes a large difference. It did take a a drop in over all life steal, but that doesn't mean this item is any less effective, it is still great item for high damage, and sustain.
+30 Attack Damage +30 Ability Power +30% Attack Speed +10% Critical Strike Chance +8% Movement Speed +250 Health +200 Mana UNIQUE Passive: Your basic attacks have a 25% chance to slow your target's Movement Speed by 30% for 2 seconds. UNIQUE Passive: After using an ability, your next basic attack deals bonus physical damage equal to 150% of your base Attack Damage (2 second cooldown). Does not stack with Sheen or Lich Bane.
Trinity force is a great item, which provides numerous boosts to your champion. It also comes with two passive abilities, one which provides a chance to slow the target by 25%, and another which is triggered upon use of an ability adding bonus damage to your next attack. It provides more stats than frozen mallet does over all, but it does not compare to it in bonus HP and Frozen mallet's slow effect is much, much better. Also of note is that Trinity force is much more expensive than Frozen mallet. However, Vi is capable of using every stat on this item and putting them to use in increasing her chase/escapability, and notably, her overall DPS.
+75 attack damage +15 health regeneration +10% life steal Passive: Damage dealt by this item benefits from life steal. Unique Passive - Cleave: Your attacks deal up to 60% of your Attack Damage to units around your target as physical damage, decaying down to 20% near the edge. Unique Active - Crescent: Deals up to 100% of your Attack Damage to units around you as physical damage, decaying down to 60% near the edge.(10 second cooldown)
This item is pretty fair, and brings a whole new capability to Vi's fighting ability. The AD it provides is high, which helps improve her AA strength, and the strength of her skills. It's Life steal percentage is low, but is made up for by the fact that it applies to the abilities of this item. Where this item gets it's power, is from splash damage. This allows Vi to not only clear waves and camps faster, but it allows her to put out a greater percentage of damage during team fights. Passively, it allows her to deal 60% of her attack damage to units around her target, but its active takes that 60%, increases it 100% on a decaying timer back to 60%. This active also carries a rather short CD, allowing her to use it often enough to really make a difference with it. This item though, while it has potential, should not be constituted over other damage items such Bloodthrister or BC(though it would work very well along side them).
+45 Magic Resist UNIQUE Active: Removes all debuffs from your champion (90 second cooldown)
Provides a good boost to your magic resistence, and it has an activated ability that can be priceless against specific enemy team compositions, namely those with multiple champions possessing hard crowd control effects. Upon activation, all debuffs and crowd control effects are removed. This is very handy during team fights for keeping you in a state capable of of not being melted due to slows, stuns, defensive debuffs, etc. It's relatively low price makes it affordable even if you should be having gold issues. It does build into another item, but the cost of the upgrade item is pretty steep, and you have several other options which could always prove to be better.
+55 Attack Damage +36 Magic Resist UNIQUE Passive: If you would take magic damage that would leave you at less than 30% Health, you first gain a shield that absorbs 400 magic damage for 5 seconds (60 second cooldown). UNIQUE Passive: +1 Attack Damage for every 2.5% of your Maximum Health that is missing.
This item gives you additional Attack damage, and additional magic resistance. It's first passive gives you additional attack damage for each 2.5% of health you're missing, which can possibly make a difference in a fight, the determining factor of whether you're the winner or loser. It's second passive is an improved version of it's base item hexdrinker. When your health drops below a certain point, You're granted a shield which will absorb 400 magic damage. This makes this a great item to have when facing a team heavy in AP reliant champions.
+45 attack damage +65 ability power +10% life steal +20% spell vamp Unique - Reload: Your basic attacks and single target spells against champions reduce the cooldown of this item by 3 seconds. Unique: Deals 150 + 40% of your ability power as magic damage and slows the target champion's movement speed by 40% for 2 seconds. 60 second cooldown.
This Item is a testament to the saying "Only gets better with age", as it did. A drop in price on this item not only made it better as it became more affordable, but it added a new passive effect to the item. While the stats of the item are all decent and pretty well off, making it strong in that one sense, It's passive and active abilities make it ridiculous. The active allows you to deal magic damage to a target(damage is amplified by a percentage of your AP). Now while Vi only has a single skill that uses AP, thus meaning you wont be build a large amount of it, this active is saved from its low damage in that department, but having a slow tacked on to the active, and further saved by the item's passive. The active ability's cool down is reduced by 3 seconds every time you attack and use skills, meaning that you have the ability to use the active of this item more then once during fights. As Vi is an AA based champion, capable of buffing her AS and reset her attack timer multiple times in a fight, she can actually abuse the passive of this item to have a sort of "5th" skill during fights.
+50 Armor +30 Magic Resist UNIQUE Passive: Revives your champion upon death, restoring 30% of your maximum health and mana. 5 minute cooldown.
Upon death, Guardian angel will revive you with 30% of your maximum health, thus the more health you have, the better off you can return with. This carries 2 benefits, as well as a draw back. It gives you a second chance to fight the enemy, allowing you to either reduce their numbers, or reduce their health enough for your team to finish them should you die again, or you're able to escape alive. It allows you a chance to maintain your killing streak, should you be able to stay alive and escape. It's draw back however is that competent players will wait for you to revive and then instantly kill you again. Keep that in mind when considering it's use.
+700 Health +30 Attack Damage UNIQUE Passive: Your basic attacks slow your target's Movement Speed by 40% for 1.5 seconds (30% for ranged attacks).
Frozen mallet is a great item on any Melee Bruiser. It not only gives a big boost to HP, but it gives a bit of bonus attack damage to boot. But it's true coup de grace is it's on hit effect. Whenever you strike the enemy, their movement speed is reduced by 40%. Do not asume that the slow will stack the more you hit them, it doesn't work that way. Instead, this item will keep your target within arms reach so long as you can stay on them.
+20 attack damage +50% attack speed +10% movement speed +10% cooldown reduction Unique Passive - Tenacity: The duration of stuns, slows, taunts, fears, silences, blinds and immobilizes are reduced by 35%.
Zephyr is a poor man's trinity force, but that doesn't make a bad item in any way. It drops the passive abilities, crit, hp/mana, and AP of trinity force, in favor of a lower cost, tenacity, great AS, and CDR. Whether you judge it by the old standard of cost from season 2, or the current new standards of cost, this item is still cost efficient. It will improve your over all dueling ability by increasing your AS and giving you CDR, make chasing or escaping easier, and the tenacity helps for when your not ulting somebody.
There are really only 2 real exceptable options for Vi with boot enchantments.
Alacrity improves your movement speed, allowing you to traverse the map faster, catch fleeing targets, or escape chasing enemies. This option is great for the fact that it can turn mercury's treads or Ninja tabi into defensive versions of Boots of Swiftness.
Furor makes Vi that much harder to escape. Because she is AA based, activating this passive is very easy, and keeping it up. Allowing her to more easily catch her query to finish them is all this is true good for though. While you can trigger the passive and then turn to escape, its a decaying boost of speed that lasts only 2 seconds, thus its ability to aid you in escape is null and pointless.
Possibly my favorite build for her. While a expensive, and you most likely wont finish this in your vast majority of games, It's balance of Damage, and defensive stats make it my go to build.