I think Fly seems like one of two pretty obvious choices for me, since it would really make transportation a lot easier, and save me a lot of money. The other one would be Recover. I don't know to what extent it would actually work, but even if I was able to heal small scrapes that I had or cure a cold, that would really come in handy.
Something a little more out of the box that might be cool to have is Metronome. Sure, I might have no idea what I can do with it, but it might be cool if one day I was able to breathe fire, and the next I was conjuring up a hail storm.