My guesses:
1) Sete Gibernau
2) Valentino Rossi
3) Colin Edwards
4) Nicky Hayden
5) Max Biaggi
I thik Valentino will fight valiantly to keep the Yamaha on top of the box, and win more than a few through sheer skill and determination. In the end though the untried bike will spit him off enough to DNF his way out of the top spot.
Sete is poised to take it, and will through consistent finishes and a proven racebike.
Colin will dominate the middle of the season after getting his bearings with the bike and team, but falter as the big boys get serious. He'll only take firsts through attrition, and then not too many.
Nicky will come on strong, and win at least one of the first five GP's. He'll have a very successful and consistent mid-season, but start DNFing later as he begins pushing too hard in search of the top spot.
Max. Oh, Max. Max and Xaus will butt heads from the first race on. The animosity and constant battles between them will take their toll, with Biaggi beating Ruben after a bizarre late season legs and arms a'flyin fall takes Xuas out for several weeks.
Of course, I could be completely wrong.
-jim