Mm.. mine beats all yall's >.<
I can.. I can research and develop my OWN augmentations! And I'd be immortal! Being able to transfer my brain body to body!
I could install new nanobots for new skills, more memory storage, new interfaces!
Dammit I'm hungry.
Maybe just an augmentation that'll enhance the velocity of my farts. That way, I could use it as a weapon.
edit: Space travel would also be a thing of the past! I could travel to neighbour galaxies without a problem! So long as I have the facilities to be able to transfer my brain to a new body when it gets old. Or I could hook up my brain to the ship!

Battlestar Galactica style.
And in that time of travel I could jot down all my observations and in spare time, research how to allow every cell in the human body to reproduce not just 50 times, but an unlimited amount of times. Giving humanity, immortality! BUT.... by the time I get back to Earth, it'll probably be destroyed...
Cause you know... time dilation. :/
Oh... one can dream.