I must say out of all late night shows, he's my least favorite. I guess what I hate the most, and I know many will agree, is when he tells a joke in the monologue and goes on for about 5 minutes about the same damn subject. Also I find his humour to sometimes be too patriotic. Although he does often have excellent guests, it doesn't make it a much better show...
Review of The Tonight Show with Jay Leno
