Tom Bombadil stands apart from the other characters in The Lord of the Rings in that he lives outside the struggle against the forces of the Dark Lords that are faced by the other creatures of Middle Earth. In many ways, Tom Bombadil represents the goodness of the world as it is when free of strife. He lives in harmony with the natural world and, at least when within his own territory, is in command of it.
One interesting thing to consider is that Tom Bombadil represents the importance of sanctuary in the natural world. He is a jolly fellow who happily rescues the hobbits as they trespass through his land. However, consider the other creatures who inhabit his domain. Barrow-Wights and evil trees are everywhere in his forest. We see that he has the power to control and banish them, yet he seems to invite them in and give them sanctuary. While he does not share in their evil inclinations, he does treat them with a certain level of understanding.
In this way, we see a glimpse into his power of empathy and good-naturedness in the face of evil, which seems not to affect him. In fact, he is not affected by the evil power of the ring as well. Tom Bombadil does not have any wish to control or dominate others, even though he appears to have the power to do so. Perhaps, Tolkien is making the point with Tom Bombadil that a close connection with nature and the natural order of the world puts one above and outside the very mortal struggles of good and evil.