HG131 said:
My mortality. I'd make myself immortal (with no aging).
I match your immortality and raise you shapeshifting (you could shapeshift into a visually identical self that doesn't age, or has super-strength, or can shoot lasers, or has more muscle, or is obscenely attractive in the 'people simply gravitate towards you' way. It is like immortality, but better.
OT:
Fine, I'll be reasonable. I'd want to be perfect physically (not necessarily 'sexy incarnate', just with a reasonable amount of muscle, perfect physiological health (no pimples, darker skin (to prevent freckling), no moles, and all my tissue and organs in peak condition). With minimal physical limitations, the only things stopping me doing what I want is my desire and determination to do so.