Since I've seen cases of "be careful what you wish for" I'll go for:
1) Perfect vision. Never need glasses ever again. No worries about driving at night. I want to be able to see detail work the way I do now (or better) and have great distance vision!
2) The ability to eat whatever I want yet still have "the perfect figure" while at the same time be healthy and physically fit... all without the dredgery of exercise.
3) The ability to know just the perfect thing to say to everyone, and to make other people happy.