Right now he's a tweener. That's why he's in a feud with a face (Cena) and a heel (Big Show). I think eventually he'll be fully heel, because he'll probably wrestle Rock at the Royal Rumble. But right now he's a tweener. Which, for the CM Punk character, is a very good position. Face for him is too corny and predictable. Heel, well let's just say he's already had his best run as a heel (Straight Edge Society), and it wont be done again. I think tweener is perfect for him. He can be the edgy "I don't give a shit" kind of character and at the same time not really hate on the fans. Kinda like it was before he turned fully face, and was going up against Cena to unify the titles after he returned last summer.