Too early to say. My take (and I've been watching F1 for many years now) on a team by team and driver analysis (top teams only):
Ferrari - sorry, Alonso won't even go close. The current Ferrari is around a second off the pace. I do not see Ferrari making this up next season, certainly not at the beginning. They might close the gap towards the end of the 2010 season, but that's it. I don't count Alonso as the best driver in F1. I'd rate Massa above him to be honest.
RBR - if they continue development on from the 2009 season, the team looks strong. Vettel will be a strong contender imho. Mark Webber is a weak #2, only capable of winning in a weak field or a vastly superior car to his contenders. He's far too unreliable.
McLaren - the team has done a massive job to improve so much during the 2009 season. They're still not quite on the pace of RBR and Brawn, but I think that they'll be on the money during 2010 and Hamilton will be a strong contendor. Kovalainen has been driving poorly.
Brawn GP - Button has to be on the money for the 2010 championship. The team is still going strongly, despite other teams catching up to it at the end of this years championship.
Reliability will be a big factor in 2010 and with FISA introducing even more narrow tyres, expect more accidents, and expect an even tighter field. Drivers will have to look after their tyres, and tyre choice will be important too. I see Button, Hamilton and Vettel all being close contendors for the 2010 championship. I think Hamilton will just edge out the other 2, simply because I feel that he's the best of the 3 drivers.
Dave