Since taking over for Johnny Carson (about 22 years ago I think) he has done a wonderful job and become an icon. He is retiring and passing the torch to Jimmy Fallon.
I was never a fan of Jay Leno. His humor is bland and most of his jokes aren't even funny. I do like Conan O'Brien but I always thought he should have stayed on "Late Night" because his edgy and eccentric humor works better on the later time slot. I think Jimmy Fallon breaths some new life into the show. Fallon is really funny and can do a lot more because he can sing and dance as well. I think the The Tonight Show with Jimmy Fallon is going to be the best ever.
I like Conan and really liked Fallon on SNL, but admit I never really watched his late night show...on too late I guess. I suggest everyone watch Jay Leno's final goodbye speech on youtube.....It's quite emotional and rings with honesty. I think even non-fans would appreciate it. I hope Jimmy does good, he definatley has the talent.