Hamilton’s best season for me is still 2007. That year he looked flawless and was possibly driver of the year in 2007. Since then including his championship year 2008, he has occasionally been very poor. Last year he was poor a bit more often than just occasionally I’d say.
Button for me was better in 2011 than 2009. He was the only driver who could consistently hold on to Vettel for most of the year. Before 2011, for Button to be at his best, his car had to be at its best, that changed last year.
I’d argue that 2007 was Raikkonen’s best year. For much of the season, especially in the final third he was on top form. His performances in Melbourne, Spa and Fuji were prime examples of Raikkonen at his best. His years at McLaren were similar, most of the time he was great, however occasionally he would show his flaws.