[Eorl of Rohan]

This is not my theory, but a pet theory I heard from someone I play WoD with who is an intense Tolkien Fan. He believes that Tom Bombodil is none other than... the Witch King of Angmar.

That is, his HUMAN SIDE, which peeks out from time to time when he is not doped up by the evil influence of his ring.
He suffers from a split personality, a side-effect of the ring which could not completely take over the powerful will of the King of Angmar and satisfied itself with taking control of his evil side.

This explains why he:

(1) is not influenced by the One Ring (he is already possessed by one of the nine rings and is subservient to the One Ring, so he is not influenced by its temptation)
(2) would throw away the One Ring if he was given it for safekeeping (he is the good - or escapist, if you prefer it - side, why would he want to be involved in the matter of the One Ring?)
(3) lives alone in the woods with only Goldberry for company
(if you knew that insanity takes over you periodically, wouldn't you want to retreat to a deep forest to rest and get away from it all and treasure the few days of sanity that is granted you?)
(4) is able to dissipate the barrow-wights, and right after that, the Nazgul somehow know where the fellowship is and comes to attack them.

What do you think? I know, too far-fetched, but do you have any concrete proof that could disprove this theory?
I myself believe that Tom Bombadil is the embodiment of the Forces of Nature itself, but he claims that Tolkien was too much of a Christian to put so much power in Nature...