Personally, I'll use every character except Toro. He just doesn't seem like a good character. But I'm actually really excited about seeing FP's, Spike's, Drake's, Sackboy's, and Big Daddy's story modes.
I plan to use everyone at least once-- including Fat Princess, as I actually like her play style. There will definitely be some characters that will fall to the bottom of the list, though; I just don't know which yet.
I like characters that use other characters to help her out in battle. FaPr was one of my faves along sweet tooth in beta. IDK the chsrs too much, but maybe cole/evil cole might drag down to the bottom of my list. I dont like heavy chars though, unless they can chain midmove, like ganondorf.