In the car flamboyance - Gilles Villeneuve
Out of the car - James Hunt
Flamboyance in the form of results - Schumacher
I saw (and felt) the Mercedes Group C car up close at Spa in 1990. It vibrated the grandstands as it went by. Schumacher did not drive that race, and I was disappointed as I had heard he was a brilliant up and coming talent. I took pictures from vantage points that could have been fatal if something went wrong - as noted above, even in the 90s there was minimal crowd control, especially in Group C Sports Car racing.
The following year I saw Schumacher's F1 debut at that same track. The thing I noticed, standing at the top of Eau Rouge, was "that guy sounds different than the rest". He qualified in the top 10 in his first race in a midfield Jordan. He never came past us at speed in the race, the car dying on the first lap.
But he did redefine what is meant to be a racing driver. While I prefer the James Hunt archetype, and I thought Schumacher was a bit of a ruthless asshole in the car, he stepped up the whole game, requiring F1 drivers to become top notch athletes. I think Senna was the closest thing to that type of approach before Schumacher.
Good topic