I'd go for Wolverine's Healing Factor....as tempting as flight really is....healing factor means I can skydive without a parachute....well pain still exist...but at least on failure I wont die. Plus healing factor means no AIDS, no aging, no cavities, I don't have to worry when I set myself on fire....pretty much invincible and ageless....sounds like if I could have one wish without making the wish super technical...a healing factor would be it.