Well the top 5 would certainly get my vote along with Maldonado
Vettel - His tyres were gone, and he had a predator right behind him hounding him down again, he was in the worst position tyre wise out of the top 3, as Christian Horner said, the team messed up the stops, put on the wrong tyres so we had to change the strategy, "BUT Seb made it work"
Alonso - Great start, came out of nowhere really to be a contender, everyone else was thinking of the race between Vettel and Button, but Alonso had Red Bull worried, how he got into that position I don't know, his car was slower than the McLaren and Red Bull, after qualifying I don't think many thought Alonso would have challenged for the win at all.
Button - Faultless race, the race was his (probably) but McLaren anticipated a safety car when Glock pulled off, made the gap up quickly, I think McLaren did have the fastest car here, but he like Vettel MADE it work. The only thing I am disappointed about in his drive, is that he didn't really look to have a move at Alonso, he just kind of sat back a little waiting for it to unfold between the front two and pounce, but I guess it was probably the best option as Alonso was making a move on Vettel most of the time (contradicting myself).
Maldonado - What did he do wrong? Not much really. He seemed to be hanging on to the top cars, he qualified well extremely well. Great race for him, but he didn't finish after an unfortunate incident.
Then there's Kobayashi, but he bumped off Sutil, and Webber aswell after being around the back of the points before the safety car.
But I have to say, the top 3 majorly impressed me, today showed why all 3 are world champions.
But I will give to Alonso, had the slower car out of the top 3, yet popped out of nowhere to give his a 3 horse race.
EDIT: (I might go for Vettel...wait...maybe Button? Alonso? Still undecided!)