I read many other theories about Bombadil. And only Tolkien would know the who or what is Tom Bombadil.
Last week I went to a conference of Joseph Pearce, author of Tolkien biography "Tolkien Man and Myth". It is a religious - catholic - point of view. And Joseph Pearce interpretation about Tom Bombadil was made in atention to Tolkiens christian faith and to the analogies between Tolkien literary work and Catholic faith, since the book of Genesis.
Some of his analogies are Genesis/Valaquenta; The characters of LOTR and Jesus Christ (the pain and suffer of Frodo, the sacrifice of Boromir, a new reign and King, etecetera); the temptations; and one analogies between Bombadil and the Eden Garden. The beggining of Middle-Earth where everything began - very spiritual theory.
By otherside, Joseph Pearce defines Bombadil as the "nature of Middle-Eart, the embodiment of the nature with his positive and negative things and with a total power inside his dominions but not ouside - Eden.
For more details I advise you to read the book..Its interesting 🙂
Ah..I share in part Joseph Pearce's theory about some kind of embodiment of nature, or in my opinion the embodiment of the Spirit of Arda, the essence of Middle-Earth.
For a sinopse http://www.christiancurrent.com/national/full_story.php?article=1276
For the more agnosticals or cepticals, don't scare yourselves with the
the spirituality of that site. Tolkien's biography by Joseph Pearce is an excellent work.
😛