I'd first get rid of my entire body and replace it with a robot body. It would be smooth and aerodynamic, exceptionally fast and strong but doesnt need to have a face or anything. Maybe two giant eyes. I would want to be able to "see" in all wavelengths of light, X-ray to radio, (I'l miss out on the gamma waves, thanks.)
I would want it to be able to fly through intersteller space with an engine that would allow me to travel from start to star and be powered by some sort of renewable source of energy (blah blah collection of hyrdogen gas or some such crap that they mention in SF books).