hmmm, too hard of a question...
These guys are the only two that matter.
Any On-Road Racing, gas or electric:
To explain: Well, Michael and Ayrton should be self-explainable. As far as On-road guys.
Lamberto has 6 WC titles in 1/8th scale alone. At one WC you did well. At two, you did very well. At three, something is wrong with you. At four, "Is this guy just getting lucky?" At five, "Man this guy rocks." At six, you are just plain AWESOME. Masami, has (correct me if I am wrong) 12 WC titles in all of classes combined.
Masami must be the wisest in R/C. His skill is just amazing. He has gone through a week of racing, and would not hit the wall ONCE.
Josh Cyrul has gotten VERY close to a WC in 1/8th scale, he must have (correct) 20-25 NC titles, if I am exagerating, you would think he would have that many from watching him drive. I have only spoken with him briefly, but he is THE nicest racer. He is very helpful, and always looks at everything from a very positive point of view. At this year's Winter Nats in Florida, he destroyed his car on a section of re-bar sticking out of the ground, I even have pictures of his car after. The next morning he was walking around the pits with his newly built car in hand, with servo wires still hanging everywhere, still not finished from the rebuild that night, 15 minutes before his first qualifier. He did get his car done to run, but that whole time, he still kept a good attitude toward everything, and still had time to speak with people as they asked him questions.
But of course, this is only MY opinion, we are all biased as you can see from reading this thread