I think that the Archangel Staff is one of the best AP caster items.

Archangel Staff-

Passive(not unique): Gives AP equal to 3% of total mana

Unique Passive: Every time you use an ability you gain 3 maximum mana

Costing less than 3000g, this item is my favorite if you are fed a lot and can get a ton of farm.

Tell me what you think is the best AP caster item!

(Please don't hate, this is just my opinion. Not a fact!)

I think it all depends on the champ, because not all casters can use mana, and not all casters have abilities that are spamable to farm up the mana portion, that being said it can give approx 140 ap to a caster with aprox 3000 mana, so it does give a lot of bang for its buck, but not for every champ. Deathcap is probably the best just because it gives huge amounts of raw ap, and it is considered a core item for almost every caster

At the end of the day it is really a matter of the base damage vs the AP ratios. if you have say 100 base damage with a .2 AP raio it would bee beter to have evil tome then it would be to have deathcap.

On the flip side of you have 60 base damage with a .8 ratio then deathcap is better.

Not to be too snarky, but 20 stack Mejai ;D

Chalice of Harmony.
890g.
Infinite laning potential, infinite spamming potential.
30 MR = ~300~ hp against magic damage.

I wonder how long it'll be before LOL DEATHCAP DEATHCAP DEATHCAP.

But overall, Rab's seems the best AP caster item due to the redonkulous amount of AP it gives, but not always. Zhonya's Hourglass is pretty great if you can use it right. Rod of Ages is one of my personal favorites, but it doesn't fit on all casters.

When it comes to sheer damage, though, I don't think any item beats Void Staff in the late-game. Dat 40% MPen.

Also: Sorcerer's Shoes are crazy good. Tier 2 boots w/ damage boost? Awesome.

ROFL, that must be Abyssal Scepter. 400G for a 20 MR Reduc Aura is definitely OP.

Deeeeeeeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaaat hcap

The answer is always rabadons or sorc shoes.