Hi there, I like your item-build as you give some alternatives and it depends on the game. I would also take deathfiregrasp in some cases. If your opponents have 2 tanks or if one of them is feeded too much. I would also try some CD-Reduction Runes. As soon as I have enough AP, i will try a full CD-Runebuild.

You might also mention the golem Buff

I would be kind, if you did read my Veigar Build(my first build) too. I dont have a comment or Vote until now. You can find the build in my Profile, if you want :D