AMA
Anthony Gobert is back on the Ducati, if he can stay healthy, I think he will take the AMA Superbike class. Also watch the Bostrom brothers, there will be some tight racing between those two.
The Supersport (600) class is too close to call, I think we will see some tight races at every event. If I had to pick someone for the 600 class it would have to be Ben Bostrom. American Honda wants the 600 title bad this year. Between the Honda factory and support teams there are some good riders competing for the title this year (Miguel DuHamel, Ben Bostrom, Kurtis Roberts, Jake Zemke, Roger Lee Hayden, Alex Gobert, Marty Cragill, Doug Chandler, Jason Curtis, Craig Connell and Ty Howard). I would not want to be on a Suzuki, Yamaha or Kawasaki stuck in the middle of that group. Can you say "help a Honda brother out and slow those other riders up".
World Superbike
Who cares, all the good riders went to MotoGP. OK, it will either be Ruben Xaus or Neal Hodgson (Ducati).
MotoGP
Could it be Valentino Rossi (Honda) again? Nicky Hayden (Honda) will have a steep learning curve this year. Troy Bayliss (Ducati) and Colin Edwards (Aprilia) will be in the battle for the title.