Jay Leno? Now?
Though it's better choice than the one made in 2007: Rich Little. I interviewed Little for The New Yorker just after he was chosen, and we talked for a while about comedy. This was my favorite part:
Little, who had a variety show on television in the nineteen-seventies, appeared on Letterman not long ago but hasn't had much other television work in recent years. "My agent tried to get me on Maher's show, but I was told that Bill said, 'That Rich Little is a pretty funny guy.' He didn't want to take the chance that I would be funnier." Little said that he does not find Maher and his ilk terribly funny. When asked to name a young comedian he admired, he responded, "Robin Williams. He's just off the wall."