User blog comment:Clizapy/AP Cho'Gath/@comment-82.238.12.114-20130127183719

You have to include Lich Bane too. It gives a great amount of AP, Mana, and its effect works awesomely well with Cho'Gath Attack Damage (let's not forget he's tied with Skarner for the highest base AD at level 18). RoA, Lich Bane, Abyssal, Frozen Heart are core items IMO, others are situational.