I think Alonso by a mile. He's either lost it a bit towards the end of the year or Massa has improved (I think a bit of both), but the guy was on another planet for 2/3 of the year.
Some of his drives in the Renault in 2008 were magic, but I think most of the season he's been driving like that. I'm struggling to think of a better season by anyone... ever.
Hamilton has been unlucky, but there's not been many days when I've thought "yeah, he's been the star". Sunday was one of them (he was relentless), but there haven't been many. That's what I thought when he signed for Mercedes, that he'd gone for the stardom or the money, if you look back at 2007, he's almost unrecognisable to that driver.
Vettel... as ever it's still hard to gauge how much is him and how much is the car, but I think it's best summed up by Abu Dhabi - He was absolutely rubbish until the first safety car, and then he was driving like Button was in Montreal last year. I just thought in the first half of the year he wasn't the guy we saw for the past couple of seasons - he's very definitely there now though.
Kimi is difficult. There have been numerous occasions when he's backed out of a move in order to stay in the race, and at the start of the season I thought he'd lost his bottle in wheel-to-wheel battles. But he's continued to rack up points while others have been tripping over each other. It's like a Prost season - never spectacular, but ever efficient. Personally I find it hard to love that, but easy to admire. Love the bloke though. :D
I think on balance, it's got to be Alonso. That Ferrari looked undrivable in Melbourne (seriously watch it again - it was
dire), and while it's seldom, if ever, been the fastest car, Alonso has only just lost the championship lead in the last few races. I think he's been driving on another planet for a lot of the season, and while he's never really looked the most naturally talented driver in F1, he never, ever gives up. It's like a super-Mansell. I'm almost sad that Vettel's got one hand on the table, and it's not through a dislike of Vettel, as I don't, but Alonso's driven so well this year that I find it hard to believe anyone could deserve a title more.