Senna: Still at his best, was awesome in 1993. If we looked at their whole careers Prost would probably edge it for me but he was way past his peak by then.
Alonso: If not for his personality he could be #1. In driving and racing terms definitely in the Fangio / Senna / Prost / Schumacher / Hamilton drawer. I think what he did in 2012 was on terms with Schumacher's in my view absolute peak 1998 season. He would have needed 11 or so points to be a 5 times world champion. His skills would absolutely merit that but he scored too many own goals.
Prost: Cruised to his last title. Fair play to him, he did everything he had to do. The ultimate master.
Mansell: A slightly tiring character but what a driver, what a racer and what a showman.
Hakkinen: Ah, really difficult one. I did watch most of his career and was never really sure myself. Saw him race several times live as well. I think his ultimate pace was mighty, not Schumacher-mighty but only very very slightly off. The issue I felt was that he had to stretch himself too far for it and hence was able to deliver it 5 times a year while Schumacher was delivering it from the first practice lap in Melbourne to the flight home from the Christmas party. I remember hearing an interview with him about one of the Italy errors and he said it was because he had to push SO hard. I was like errrmm good morning, that's what Schumacher had to do non-stop between 1991 and 2000. Looking at it differently, he would have been the class of the field in the second half of the 1990's if not for Schumacher. How on earth did he manage to almost lose both the 98 and the 99 titles with that car I will never understand. When Schumacher had a car like that he was World Champion by July. And against Eddie Irvine of all people, FFS. Not top drawer but two world titles don't sound unjustified.
Raikkonen: Insane natural talent, no nerves but not much skills in building teams and developing cars. His peak in 2005 was a joy to watch, I kind of think the title two years later was the reward for that, not for his already declining performance in 2007. I also appreciated that he didn't care and actually his short interviews were often the most interesting ones because he was giving actual answers, not what the PR person told him to say.
Rosberg: Much better than what people give him credit for I think. Imagine Barrichello taking a title away from Schumacher. Sounds absurd, doesn't it? He really needed every tiny detail to be perfect to beat a faster driver in the same car over a whole season and he achieved that.
Hill: an extremely rare case, mediocre all the way up then suddely the F1 cars suited him, which I don't think anyone expected. Totally outclassed by Schumacher but a remarkable man and I think a world title is a fair reward for a good season in 1996 - he had to win it really in that car against a rookie, second-rate team mate and he did, so well done.
Montoya: fantastic talent and a fearless racer, a joy to watch. A bit more brain would have helped him an awful lot.
Coulthard: a good driver, could possibly have beaten Hill to the 1996 title if he had stayed but Häkkinen was beyond him. Reliable, professional, I think being managed by Brundle helped his career a lot.
Villenueve: he should be grateful to Phil Hill for not being the poorest World Champion by a countrymile. Developed into a really nice bloke by now, I have to give him that. I like him as a person.