I'd augment my brains, increase my mental capacity, improve my memory, reduce the learning curve to everything, and second, I'd sort of augment my agility, speed and stamina(basically make myself extremely fast and make my movements extremely accurate).
Third, I'd get a computer implanted in me, so I'd be able to browse the net with my eyes, and watch films from my own head. Would be great fun.
Actually, no, scratch the third one, give me augmented bones and cartilage, and give me a bit of genetic engineering - remove all junk from my DNA (96% or so of our DNA is genetic junk, afaik), and make it so the telomeres at the ends of my chromosomes don't degrade when they multiply... so in short, give me biological immortality, by which I mean I wouldn't die from old age or disease. >.>