I'm gonna add another one to David Freiburger, but not because Roadkill. While the smashingly sucessful YouTube show has made him incredibly noticeable, I've followed him and his career in car magazines for quite a long time now. He's been the editor of several enthusiast magazines that, before his direction, were almost impossible to read.
He revamped Rod & Custom in the early 00s from a boring, uninteresting pile of junk and made it a magazine with attitude and actually interesting and fun to read again. He then did the same with Car Craft, which looked and read like a magazine made in the early 80s, and revamped into one of the funniest magazines I've ever read (think Roadkill in print), but also one of the most interesting and useful.
He then started his fooray in Hot Rod and his touch was immediately noticeable, as the magazine had strayed from the well-paved path it was running in since the late 90s. Freiburger literally saved three of the magazines with more tradition and heritage in the hot rodding world and made them interesting and fun to read again, and I was always amazed with the before and after of some of them, you don't have an idea of the kind of change they suffered the moment 'Burger hopped in.
Roadkill is like the culmination of all he's done in his journalist career put into video with him goofing around with Finnegan, but the thruth is that Freiburger has done more for car culture than most people really realize.