He was my favorite, I wished he would have had a bigger role in the series. And I think its kind of funny that he was added as a character in the Lego game and not in the actual movie. And JRR wanted to make his own mythology, he even invented languages and his own creatures. Tom was just one of the many parts of what made up his story
He was an ancient who passed on wisdom and items. I didnt like his character as he always seemed forced onto the scene. I'm in the minority in this area though because I know a lot of people who love Tom Bombadil.
If you read all the way through he actually holds one of the rings which Gandalf shows up with in the when the elves leave middle earth
What? The three rings originally belonged to Galadriel, Gil-Galad and Círdan. Gil-Galad's ring was eventually given to Elrond and Gandalf received Círdan's. The rings are "a means of power," and Tolkien himself states in The Letters that both good and evil desire a measure of control over this power. Tom Bombadil, however, has renounced control and takes "delight in things for themselves...watching, observing, and to some extent knowing [them]" (179), so to him these means of power are valueless.
Tolkien himself has called Tom an enigma, saying that even he doesn't really know who or what the character is.
Precisely. He felt all great mythologies needed some things that can't easily be explained. Bombadil is his "thing" that no one really understands. He may be important, he may not be. No one can be sure.