I would argue that Hamilton didnt have the best car in 2008. In fact for many races, I remember Ferrari being able to run away with it. You also saw how Hamilton comprehensively outperformed his team-mate.
Compare this to say Ferrari, who include a very fast dry weather driver (Massa) and the then, World Champion (Kimi) - Hamilton dealt with the situations in 2008 pretty damn well, for his 2nd season in F1.
If you go back to 2007, you will see that he managed to handle the then World Champion (Alonso) and matched him on points. In some races, he even showed he was faster than Alonso. And all this in his first season in F1.
In 2009, Hamilton continues to show that he is special in that he is finishing races in positions that his car, by right, shouldnt be finishing in. Compare Hamilton with his team-mate and you get a good idea of the true performance level of that car.
Button is a good solid driver, in the same way that Kimi was in 2007 and D.Hill was. These drivers tend to become forgotten, soon after they leave F1.
You cannot mention Button in the same breath as Hamilton.