I seem to be in the small minority but I always found Tom Bombadil to be one of the most curious characters in the LoTR, it's a pity he's usually edited out in adaptations. And he's no transient character either, Tolkien later wrote poems about him and he's also mentioned in The Return of the King.
Truth to be told I was extremely fascinated by the fact that the first character Frodo encountered in his journey was T.B., the only character in Middle Earth upon whom the "one ring" had no power at all. He wouldn't disappear.
However, the fact that Gandalf brings in many reasons to avoid hiding the ring there IMHO, was always kinda curious.
He is underneath nature, primal and original. The ring was nothing to him; it changed things in such a trivial way, to his understanding, as to be irrelevant.
Well heres my single data point. 20 years ago, young me had to pick a nickname for the first online adventures. All the popular LotR characters were already taken, except Tom Bombadil, so I begrudgingly used that.
There might be a bias when it comes to presenting oneself as the 'fellow whose boots are yellow'. For some people it is not a problem; there's even a punk-rock band frontman who claimed Tom Bombadil is his alter-ego. On the other hand in 2012 I role-played a pastiche character of Bombadil at a major larp festival and everyone agreed that in the over-twenty-year history of that game, a couple thousands of participants for sure, I was the first to do so.
(in doing so, I sticked to the leprechaun interpretation of T.B.; not a Dark Lord as the linked article would like to inflate, but not a goody-two-shoes either. Mind you, these leprechauns have as much in common with green-irish-hat figure as elves with Santa Claus elfs)
Everyone i spoke with loved Tom bombadil andò was sorry there wasnt more about him in the Books. Maybe it's a cultural thing, or just a very polarizing character.
I don't quite buy the explanation given in this post, although it was an interesting read. I think Bombadil is beyond good and evil, he just is. From http://scifi.stackexchange.com/questions/1586/who-or-what-wa...:
"And even in a mythical Age there must be some enigmas, as there always are. Tom Bombadil is one (intentionally)."
The Letters of J.R.R. Tolkien, No 144, dated 1954