Actually, it was Jason Kidd who won it last year, with Payton coming in second.
I think this year Payton has the highest chance of winning the competition, especially since he did pretty well last year and will most probably be better this year (now that he's got the experience). Marbury will have a pretty good probability of winning it too, due to experience as well.
Boykins should be pretty fun to watch. Many will be rooting for him just because of his size, and that will include me too.