I want all of column A and all of column B.
As has been previously stated, Colbert is an actor, putting on a show every day, the end result of which being hilarious, all the time, every time.
Stewart is like a real newscaster, only ripping everything he reports on to shreds, the end result of which being hilarious, all the time, every time.
However, if I had to choose, I'd go with Jon. He can make anything funny, he can make serious points intelligently, and if he has a guest on who he disagrees with he can verbally kick his or her ass (in a respectful manner, too!)