I was told a long time ago that light-colored beers didn't age well, but you can just ignore that advice. Belgian Tripels age WONDERFULLY as Richard pointed out.
(I tried a 30 year old Westmalle tripel for my birthday last year and it was AMAZINGLY good.)
Seems like strong is really the only requirement. (And bottle conditioning helps; then again non-bottle conditioned beers will oxidize faster which will get you aged flavors in a shorter period of time...)
Adam