In some ways, MMA is like a lot of other sports. Across the board, the younger guys, the phenoms, the tantalizing prospects, tend to capture the imagination.
Here are 20 young fighters I believe could hit it big on the biggest stage (that would be the UFC). I didn't limit this list to current UFC fighters, given that the UFC can pretty much sign whomever they want. I did, however, define young as 25 or under, with apologies to Junior dos Santos and Jake Ellenberger, among others.
Finally, "greatness" is a bit of a slippery term. I don't want to imply that I think every one of these fighters will be superfly hall of fame champion some day. So maybe what I really mean to rank is those on the path to goodness, if not greatness.