Here's my take...
Ferrari I'll start off with some controversy. Ferrari is a third-place team. I know, everyone says they're the team to beat, but I see through all their big-talk and fancy lap times and I know their weakness - and it's a doozy. The Ferrari eats tires like the cookie monster eats oreos. Sure, they can do a 40-lap stint, but only on hard tires with their lap times slowly inching up, whereas the other teams are able to lower their lap times as the fuel burns off. And on the soft compounds, I'm surprised that there isn't a visible cloud of rubber trailing behind them.
I know I'm completely out on a limb on that - it's dead opposite of what I've read pretty much anywhere. But I can't help but go back to the final race sims in Barcelona...

You can see what I mean about the Ferrari. They can manage to just keep their lap times even as the tires go and the fuel burns off, but then they get new rubber and fly. The Mac and Merc, on the other hand, seem much easier on the rubber. The first stint is the most important in this regard, given the fuel loads and everyone fighting for position. Massa just killed this particular set of tires, while Schumacher, Button and Alonso managed to at least get theirs to hold. Hamilton's first stint is scary. His entire race sim is scary - I mean you can't even tell where he pits.
The other thing is that while Ferrari might look fast now, they've got no new parts planned until Barcelona; and unlike the other leading teams, they've already got their car pretty much tuned in. So on both counts, there's less room for improvement over the first races.
So yeah, they look quick, but they're not quick enough, because...
McLarenWDC, WCC. I think they're in a perfect position with the car this year. It was quick out of the box - fastest lap times in all but one of the tests, fastest trap times in all of the tests; it responds well to updates; they've thoroughly mapped out the aero in real life conditions; they've got an update planned for the first race; and they've been more than a bit coy in testing. And as quick as they are, both drivers still say that they're only just now getting into doing setup work.
Not to mention all the complicated gadgetry and cheatery that I'm sure they've yet to completely understand, much less unleash.
This car has legs.
MercedesI think they had a bit of a slow start this year. They didn't have the car ready for the launch, had difficulty understanding some problems, and weren't able to get any real updates out during testing. Nonetheless, the car is still quick, and I don't expect Brawn to let his team languish. They'll have a big update in Bahrain, and I think that will set the tone for the season. If it's good, then they'll be the ones to take the fight to McLaren throughout the year. If not, well then they won't. As close as they are, I'm expecting their update to pull them ahead of Ferrari in Bahrain, but not ahead of McLaren, only because they'll have updates of their own.
Red BullYou never know with them. Last year, everyone had them pegged as solidly mid-pack, but then they came out fighting and almost won the championship. I think they're a bit quicker than they let on; though I expect the extra speed is along the lines of what McLaren and Merc will show. So - I
think they'll be fighting Ferrari for third, but who knows.
Force IndiaIf last year wasn't enough of a demonstration, this year will prove to everyone that the key to making the independent teams competitive is through partnerships and customer cars. FI's tie-up with McLaren is deep enough for me to consider them a customer team, and I think it shows. They'll do well this year; every bit as well as...
SauberBMW is gone, but Peter got the house in the divorce. And the kids. And...
The only problem is that he didn't get any of the sponsors. I think they'll start well, but the money pinch will show itself soon enough. Expect them to surprise at first, but fade as the year goes by.
WilliamsCosworth's great hope. Solid team; solid midpack performances. They'll fight it out with STR, Renault, and Sauber.
STRIf you liked last year's Red Bull, you'll like this year's STR, only with worse drivers.
RenaultGood driver, but I just don't hold out much hope for the team. Too many personel changes, too steep a drop in budget.
LotusVirgin is faster right now, but Lotus is more likely to last.
VirginThis team is an underrated threat to finish races, I
think.
CamposLate to the race. Later to the finish. If they show up.
StephanMaybe it's just me, but I don't think that 40' shipping container looks all that aerodynamic.
USF1Yeah, right.