I just started watching old episodes en masse. I'm not a huge car guy but the show is hilarious. Clarckson is really the star. Hammond is the least funny. James May seemed to be a third wheel at first since he gets less air time than Hammond, but he's more funny.
James May is my favorite. He's quirky, always has something funny to say, is genuinely interested in how the car works and what makes it special or innovative, and is definitely the brunt of most of their jokes. Good dude.