Vacuum, speed bleeder, or..what's the best one man bleeding system?

Pardon my ignorance, but what exactly is gravity bleeding? Is it just like it sounds? Crack a bleeder open and let er flow?

Yup. Remove the M/C cap, make sure it's FULL, crack the bleeders one at a time starting in order rr, lr, rf, lf. At least, that's how I do it and it's never failed. Let them drip one at a time until you have nothing but fluid.