I think that list totally has the 5 right guys in it. Not sure if it is the right order (ie. Alonso may be better than Hamilton), but I have to say I'm pretty much behind that.
In no way is Jenson Button one of the 5 best F1 drivers of today. He's got no chance of matching Hamiltons pace next year, I think... (Not that he's bad though)
When it comes to all time bests... Now that's a lot more difficult.