They all take turns. Although Josh Hutcherson is the only one I've begun tweeting. To my own personal embarrassment. I'm older than a teenager. By a bunch.
I don't care. I feed my inner teenager and usually tell everyone I'm middleaged.
So, I guess by the strength of this answer it would have to be Peeta. But you have to survive his Book 3 Tranformation by the Capitol. That's such a juicy turn of events. Katniss in the book just flat out writes him off.
I'm still desperately trying to work out how Peeta gets from the Burn Unit unencumbered all the way to the Execution Arena to foil Katniss' suicide. But gosh darn, it's hard to love him much before that. I can't wait to see what Josh does with the third book. I know he's done a few 'serious, upset' scenes, but I hope that the direction he gets in this movie will help mold future dramatic characters down the road. He certainly comes off as a nice, smart man in interviews. I'd be willing to bet he takes good direction, hopefully he likes working with the director, 'cause I'm sure he likes working.
They're already at work on "Catching Fire". WoooooooHOOOOOOOOOOO!