Comprehensive item list: When to get what
These should be your standard boots. They maximise your damage. You want damage.
Good for ganking mid game. If you won't be able to kill your mid lane, or other lanes seem highly gankable most the time, these can be a good purchase.
Very situational, but can be effective. If an opponent relies on CC to burst you down, these are worth looking at. For example
. Although, you could still just go sorcs and kill them first. Decisions, decisions.
Early game item choices
This along with sorc shoes, standard runes and masteries will be causing you to do close to true damage against your opponents with MR runes, making them easier to burst. The health will also make you a bit bulkier. This is an effective item choice if you want lane dominance and early/mid game power in general. Do not upgrade this to Liandry's though (Explained later) and if you reach full build you should probably sell it, however it's very rare where you will reach that point.
Slightly less early power than the haunting guise, but builds into a deathfire grasp which is a core item on Annie. The CDR is nice to have as well.
Get this if you're struggling in lane against heavy harass or you really want to go RoA this game. Generally not a good choice if you want to dominate your lane as it gives you no killing power.
This works really well with boots of mobility.
Boots of mobility and mejai's? I know what you're thinking. "This guy's an idiot." Well, this build is great for carrying soloqueue games.
If you go this route, the aim is to push your lane out. Walk to either top or bottom lane in no time at all, and kill them. Or hell, go into the enemy jungle and hunt for them. If you can do this successfully, mejai's obviously fits in well. This is incredibly effective in soloqueue, as the more lanes you win for your team the more chance you have of winning the game. If you win mid and bot lane for your team, you will win the vast majority of your games.
Especially useful against AD champions. Pretty much a must buy against champions like Talon.
Core item choices
The bad news is that this no longer scales with AP at all. The good news is that it still helps you blow up a single target especially effectively. It goes without saying, but make sure you lead your combo with this.
The king of AP items. This gives you the most AP on a single item and makes all your other AP items more effective. Rabadons is never a bad choice. You want to be killing things and this helps you kill things well.
As mentioned earlier in the guide, Annie benefits hugely from HP once she has a few points put into
. Add on good lane sustain and decent AP, and this is a great item for Annie when bought at the right time. However, the time it takes to charge to effectiveness means you need to get this relatively early for it to be at full strength in mid game teamfights, which is the point of the game where Annie is most useful.
I can't understate how important magic pen is. If an enemy has 100 magic resist, you will only do 50% of your raw damage. With just a void staff, you will reduce their magic resist to 60, causing your attacks to do 62% of your raw damage. This is not even factoring in the AP the item itself gives. However, remember that this item works as a % of the enemy MR and the less they have the less useful this is compared to building raw AP. Also remember that you should be focusing the squishy target, so just because an enemy tank has 200 MR, if the targets you're going to focus only have 50MR do not bother with this item.
If you find yourself flash initiating fights for your team, this could be a very good item to pick up. Otherwise you could find yourself getting instagibbed once your stun wears off. If you flash, R, Q, W then use the active forcing your opponents to focus somebody else, you can then come out and use E, Q, W straight away giving you another AoE stun.
Other items to consider
This is a relatively situational item but it does have its uses. For a start, it once again counters high burst AP champs that may be able to otherwise combo you from full to nothing. It also works well with a double AP comp (Or with any champion that does moderate AP damage), as the reduction of MR benefits any magic damage dealt to the target. However, for the aura to work you're going to have to be near the enemy team. This makes it synergise well with the zhonyas tactic mentioned above. It does also allow for better trading in lane against AP mids if you get it during the laning phase.
This item is relatively cost-inefficient. Mediocre health and AP. You're paying for the slow here. Two of your skills are AoE so apply only a minor slow. I personally don't think it's worth having a poweful slow on only one ability, unless you're up against somebody who really needs the movement speed, but even then there should be people better suited for countering said champion. However, if you just need a chunk of health and it's too late to get a RoA then it isn't an awful choice.
This item is great. If you have an important fight coming up make sure you have this active.
The health and mana is great on Annie, however the active can easily be popped by any poke ability. Situationally could be useful as a late game defensive choice against certain champions that can win a fight with one skillshot (Blitzcrank) or any champion that needs to hit all spells to combo you (Leblanc)
Your spell combos will be done too fast with no attacks in between, meaning you lose proc chances. It could possibly work well in a glass cannon build if you sit at the back and fire Q's and autoattacks every two seconds with 700AP. I'm yet to try it. But until I do, I'm leaving this item here.
Okay, this isn't an outright bad item. It gives okay AP, nice CDR and it does let you spam without blue buff. However, I just do not consider it to be an optimal choice. Consider it as an option if you're not going to be getting your own blue buff and need some additional MR. Very situational.
This is something I have never tried, but could be quite effective in theory. As I've repeatedly established,
makes building HP on Annie more effective than most other champions. With RoA and Warmogs...you're not going to go down easily. It goes without saying that this dents your damage and as such should be saved until after you have several main AP items. This is also reliant on your team having a good damage output, as you'll be taking more of a tanky stun role than damage dealer.
Cheap and effective. Useful if you're being targeted by CC, but that probably means you're in a bad position or the enemy team isn't very smart. Situationally useful though.
I just don't think these stats benefit Annie enough. The CDR is nice, but masteries, DFG, blue and blue elixir will leave you pretty much at the CDR cap. There are just better choices generally. Maybe consider if they have a Mundo who's being problematic.
Items to avoid
You do not need the mana. This is bad. Oh so bad.
Deals damage based on enemy current health. After a combo they should be very low health, if alive at all, this item is relatively useless on Annie.
This item is great on bruisers. But for Annie...well I'm not a huge fan of it. I think it simply costs too much for what it gives. The revive means nothing if you die in a bad position, it just means you'll get instadropped when you're back up. It can make the difference between winning or losing a fight...but it could also be totally useless. For the cost, it's simply not worth the gamble in my view.