I'd figure best zoning would be Dhalsim since he can control space at nearly every level.
Best turtle...Guile? Down back, sonic boom recovers super fast, standing uppercut or flash kick for jumpers. Once in a while throw a slow sonic and walk up for a backfist?
Best rushdown...Cammy, Seth, maybe Sakura? I don't know.
Raida me this, raida me that...