I remember rounding-up a bunch of "standard" 14awg power cords and listening to them, and picking the one I felt gave the best overall performance. I can't recall the specific brand - that little factoid is lost in the mists of time ;-)
Mingles is certainly correct - gauge is only one of the many factors that affect power cord performance. Try to get a few different samples to evaluate and see what you think. There are a lot to choose from these days (!) in all price ranges, but many of the good ones aren't too expensive.
Have fun!
Best regards,
Steve McCormack
SMc Audio