I agree with the general consensus...given the options you've mentioned, I'd go with cherry. My FAVORITE way to cook ribs, though, is over a mixture of pecan and apple.
I agree with CGH in that if I could "only" have one wood, I'd go with oak - BUT, it's fun to experiment with different flavors and wood selections.
Pork loves fruit woods, so try the cherry you've got in combination with some oak or pecan, or branch out and try some peach, apricot, apple, or plum wood - all awesome with pork, and all combine well with oak or hickory.
As mentioned numerous times before, the most important factor in cooking good ribs isn't WHICH wood you use, but HOW you use it. As long as you've got a clean-burning, cool, blue smoke, you're probably going to enjoy what comes out of your cooker.
Good luck with your rib cook!