I actually reckon Schumacher is the greatest. He is not the fastest today, but he is the one with the most championship titles and that is a measure of greatness as good as any (as it excludes any personal bias).
Fangio was also extremely succesful and was perhaps a "better" driver than Schumacher, who knows? Senna and Superswede Peterson both died before their time and who knows what they could have achieved if allowed a full racing career?
Or...
Is Jarno Trulli the greatest? The slowest guy ever to stay in F1 for so many years?
