I haven't put my vote in yet because there have been so many 'best' drivers for very different reasons...
Chandhok, Senna et al deserve some recognition after Bahrain - Chandhok getting his first two laps in his car and Senna managing 18 after pretty much no testing or development...
Jaime Alguersuari - has got to be one of the most improved drivers of 2010, he has completed every race (and must be in the minority with that feat) and has finished in the top 12 the majority of the time. If Webber was to move on after his turbulent season with RBR I could easily see Jaime being moved from STR to play with the 'big boys'.
Hulkenberg - for the best pole of the season!
But my top 3 after some deliberation...
3 - Kobayashi, the overtaking king of F1 after this season, very entertaining!
2 - Kubica, reviving Renault after some very bad press and getting them noticed again for all of the right reasons!
1 - Kovalainen, always liked him, was a very good 2nd driver for McLaren and has been much better than Lotus's so called number 1 driver. Out performed the rest of the new boys this season and will hopefully get back into the top half of the Drivers Championship
Ok I'll vote now...