I don't think the test so far give us the full picture.
I've heard that Newey has again done a fantastic job, and that Red Bull will also this year have a large advantage from the get go. If they in addition have less faults and make less mistakes, they should be leading the championship from start to finish. And I think Vettel will be both confident and relaxed, and will get the upper hand vs. Webber.
Ferrari will also be very strong, very close to Red Bull in race pace, but now qualifying. Massa has a lot to prove, but I think he will mess up as he's not the cool customer like Alonso. Which I'm convinced will overshadow him once again.
I'd really wish McLaren would be up to the job. But I don't think the car is good enough still... Will have some straight line advantage, but the bulls will kill them in the curves...
Furthermore I think it will be another embarrassing year for Schuey... at least they've stopped blaming the front tyres now. Rosberg will kick his behind all 2011 is my bet. MS is passé...
Btw I won a bet based F1 "fantasy league" competition last year
My money were on Vettel, Alonso and Ferrari.
So my bet will be very similar this year...
1) Vettel
2) Webber
3) Alonso
4) Hamilton
5) Barrichello???