Who's older?
 

Tolkien can be somewhat inconsistent in his writing, like with that whole Winged/Unwinged balrog thing. So, with Treebeard and Tom Bombadil, who is older? Both claim to be the oldest creatures on earth, and that they were there before everything else was. I very much doubt that they were born, or created, at the very same moment. so is there any evidence that tips it to one side or the other?

I think Treebeard. Though I'm not entirely sure. But that's what I thought he was implying anyway.

Well, I would assume that they're both correct in different ways. First of all, this thread already discusses the question of who's oldest. And on this most excellent thread, burrahobbit put forth a very interesting argument about Tom Bombadil that would answer all questions on that subject. Hope this helps!

If we look at it closely, we'll see Eru is older...

Oops, I thought I did a thorough search on it... okay, thanks!

Eru is ultimately the oldest, then come the ainur. Both Bombadil and Treebeard are called the oldest, but Gandalf is older than both (unless Bombadil is also a maia). It says in The Sil that the Ents were the first creatures to walk on ME (aside from the ainur), but Elrond says something like "in that case Iarwain will leave this world last, just like he came first". They both seem to be oldest, no atter how you turn it.