AA and Bully Ray are my favorites. AA makes me laugh quite a bit, but he can be dead serious as well, and Bully.. well we all know how great he is.
Punk is good definitely but he can get awfully stale and seems to drag on a bit at times. It can get really, really boring (Personally, I haven't "marked" to any of his promos aside from "the shoot"). He's not as perfect or as great as a lot of people make him out to be, imo.
I also like Bryan, but would love to hear some more serious promos from him.
edit: Heyman definitely needs to be on my list