Exactly, completely agree.
When he first got to Ferrari they were nowhere. He took an uncompetitive car and fought for the title until the last day for 4 years. He played a huge part in making the team what it is, because a good driver isnt simply about being fast and winning races. It's about being able to notice small changes in the car's behaviour and being able to convey that to the mechanics and engineers, working to improve the car, testing, giving input in setups etc. And that, along with his speed, is what makes him the best there is. When he broke his legs in Silverstone, first thing he said when they got him out of the car was "Tell the team to check Irvine's brakes".
This season, Ferrari's overall package is probably 5th, maybe even 6th best. McLaren and Renault have the best packages on the grid, but IMO BAR Honda and perhaps even Toyota or Williams have at least equal if not better cars. Yet, whith an objectivly mediocre middle of the grid car he's 3rd in the drivers championship standings.
Where's Barichello? He's eight, only 3 points infront of Nick, who would have probably overtaken him had it not been for his problems today. Button would also have more points if not for BAR's problems with the disqualification and deduction of points. Thats where the Ferrari drivers should really be, between 8th and 10th, yet Schumacher is 3rd.
Thats what makes him the best driver on the grid, the fact that he is always able to bring the most possible out of the car, and thats why he ran away with the championship on the last few years. Remember, Rubens was never really safe in second place, there was always someone that could endanger him. Schummi was so fast because he is the best.