I've thought about this one previously, have to go with flight. *edit* (didn't read entire op) - I guess it be nice to see the world from a different perspective/travel quickly - all that stuff; save a good bit of travel money too.
Flight would be nice...but I fear that I would be captured and experimented on...so I'm going with Invisibility.
Could just "borrow" money if I needed...go any where...although, I would have to move somewhere warmer as I would need to technically walk around naked.
Definitely invisibility!! Healing powers would be a close second, but being invisible would give so many more opportunities! (Not least the ability to kick a real douchebag that I know and get away with it... )