I'd give myself the ability to fly, immortality, and invincibility
Nah in practical terms I dunno, maybe make myself 6' 3" instead of 5' 11"
Maybe make myself a bit less cynical
I'd also have a bushy beard instead of this crap I call facial now
If given the choice of being one of the first people on mars, would you go, but without possible hope of return for at least 25 years.