I tried to make shaco one of my standard champs last month. I play solo mid, and what I found was disturbing. It's like Numbr1 En Brazil said; shaco scales off of bad players. I played AP shaco against some friends and kicked their teeth in, but other's stomped me. I took Shaco to support bottom for a few matches. Some I fed my carry and some I fed theirs. I took him top. Nary was there a bush to hide in for the enemy. Fun stuff.

I think that Shaco does best in the jungle, because that plays to his ability to start without a leash and get to ganking as soon as level 3, or even 2 if you're feeling gutsy. I haven't upgraded my build for him, but I found that if I rush wriggles, then brutelizer and then infinity edge I can pretty much stay at about the same thread level the entire game. The ganks are what make or brake him; your shiv only does so much to keep the person there and that can be a problem when you rely on kills.

Would personally like to take him AP again. I'm working on a way that I build him CDR and spell vamp and make him into an AP melee assassin. Will it work against smart people? We'll find out.