As Nordic well put it, Senna did make numerous charitable contributions. However most top athletes making millions generally do (At least over here. Most top baseball and football players have charities set up in the communites in which they play. Here in Cincinnati many of the Reds and Bengals have charities they contribute much time and money to.) I ridiculed Schumacher for having to issue a press release last year noting his donation to the tsunami relief, I thought it very self serving. Tiger Woods donated millions to tsunami relief as well (his mother is Thai after all) but didn't utter a peep about it.
Regarding the Nige

I freely admit most of my opinion of him is coloured by his off track demeaner. Good grief! The endless pissing & moaning, and as Andy said, the post race hysterics, etc. The guy had the world by the balls and all he ever did was bitch & complain the moment someone put a microphone in front of his mug. Rick Mears used to say that he had to pinch himself every morning when he woke up, he just couldn't believe he actually got paid to drive racing cars, and nobody would ever be able to wipe the smile from his face. Whenever Rick signed a autograph he said "Thank you" to the recipient of the autograph. There are a great many people of all professions who should learn to accept fame, success, and wealth with such grace.
Nigel was never a pretty driver to watch (in fact I would describe his style as downright butt-ugly at times), and never a great qualifier. But he was probably one of the best overtakers in racing history, and ferocious in battle.
Fax