definitely put a brake on if it's your first fixed gear.
if you really want to get into the aesthetics, you could get non-machined rims, run a brake for the first little bit until you get the hang of it, and then take the brake off. that probably wouldn't screw the finish up too much.
or you could get a machined rim in the front and a nonmachined in the back
either way, definitely learn how to skip, skid, stop quickly, and that sort of thing before going balls out and brakeless.