he is really bad. his interviews are so constructed, and his skits are aweful. letterman is much better, but IMO Conan is the best. he can be hit and miss sometimes, but his hits are goddamn funny as all hell. anything Triumph the Insult Comic Dog does is golden
Late Night with Conan O'Brien is the best. Conan has the best bits. His self-depracating humor is funny but also sometimes too repetitive. And yup Gringo, anything with Triumph is great. I don't even need to get into the Star Wars one or the Hollywood Squares bit. I thought the show would go downhill after Andy left but it's still great. I still need to go see a live taping. Some of my friends have gone several times and said it's so much better actually being there, so I think I should go check it out soon.
Jay Leno seems really sleazy to me. The few times I've seen him on TV, his jokes were really obvious and limp, his hair was unnerving, and he was all-round awful. Johnny Vaughan and Graham Norton are far better.
Leno is a TV-dinner. You know exactly what you are going to get, it's going to be bland and not offensive. Why eat it when there are so many more fulfilling choices? Letterman is the best at improv when he is on his game but often he is in a bad mood. Conan is good and has the best skits. Stewart is probably the best overall. He is awesome and a soccer fan! Graham Norton is hilarious but would his show fly in America? He wouldn't be as good toned down for network TV. If HBO picked him up for a late night slot right after Sex in the City that would be ratings gold.
Conan is great, but no one has mentioned my favorite, Craiggers. Mostly only for his short monologue and In the News, what I do is tape just his monologue and In the News and watch Conans monologue and first comedy bits.