Hamilton is the fastest in terms of pure pace in my opinion. However that does not necessarily make him the best e.g when Kimi was in F1 he was arguably the ‘fastest’, but other things make you the best. This year Hamilton has been inconsistent and overdriving the car.
Alonso is the most consistent (able to be at his maximum level of performance for prolonged periods of time.)
However on this season’s form (not ’07 or ’08 Hamilton fans) Vettel is currently the best driver in Formula One, as he is very quick and very consistent merging the best attributes of Lewis and Fernando.
I just wish Mclaren and Ferrai can increase their competitiveness next year so we have a proper title fight.
Oh and Di Resta is the quickest rookie, Perez has potential but I can definitely see Paul winning races in the future if he has a good car.