You've probably heard pro cyclists talk about power to weight and other fun terms like "Vertical ascent per minute" or VAM for short. Your PW ratio basically determines your VAM, ie how fast you climb a vertical distance per minute. Having incredible power doesn't win you the tour de France, rather having great power and low weight does! Surely Jan Ulrich could put out more raw wattage than Lance, but Lance was significantly lighter and hence faster uphill.
All of this to say that I have been on a quest as of late. And that is to improve my PW by trimming off some unnecessary pounds. With diligent nutrition and training, I am down from 175 and 16 percent body fat to 156 lbs and low singe digit body fat. Needless to say I am stoked. Hope I haven't lost significant chunks of power in the process!