Bombadil is too silly for me. He is, at least to me, the ultimate ADD patient.
Therefore I would have to pick Gandalf.
++Gandalf
I don't vote for Gandalf because I dislike Tom Bombadil (lots of people in this thread are simply voting the other way because they don't like the match up), but because I really enjoy Gandalf better than that crazy "jolly Tom". Tolkien's way of sanctifying a prophet in his myth, Gandalf shows the true selflessness of a leader, and he is the only one out of the five Blue Wizards who stay true to the original purpose of Eru. We see the best of him as a care free old wander while in the Shire (as a rule only, as Aragorn states) and we see the cunning wise wizard that he is while he executes his plan to unite the free peoples of Middle-earth to fight against the forces of evil. Yet for all that we know about him there is still a sense of mystery around him, not even Galadriel knew his full purpose.
Anyway, I think Gandalf sayed it best in the comparision between him and Bombadil when he said: "He is a moss gathere, and I am a stone doomed to rolling."