Both Conan and Leno are annoying. Conan is funny, but not as funny as he thinks he is. Leno is just plain irritiating, he's so smarmy and mean, and it seems like at any time, any second from now, he's going to offer the audience a used car to sell

Craig Ferguson, now
that dude's funny. And he seems so genuine as a person, too. His monologues are the best because they actually have some plot and content behind them - he tells a story, almost - everyone else just has a series of unrelated jokes as their monologue.
For example, a non-comedic reason I like Craig because - besides a couple of lighthearted jokes - when Britney Spears was going through whatever she was going through a couple months ago, he took it seriously and didn't kick her when she was down (and when he mentioned this, he implied how cruel all the other talk show hosts were by doing so, which was true)
(though Craig's monologues are scripted, I read that in an article about him. However he writes a very large amount of them himself, and sometimes ad-libs when things go wrong - and he has a wonderful delivery, so it seems like it's all so spontaneous)
I like the late-late show,it's just funny on how he can just ramble for a while.