The GoPro seems to be a popular camera around these here parts. I also think there is a much better solution out there, MUCH BETTER. Take a look at the CONTOUR series! Built for rugged outdoor use, image stabilization, GPS if you want it, plug in mic version to locate the audio out of the wind - put the pickup right where the sweet spot of your motor sound is. This one is a no brainer for me.
Contour >> GPS Video Camera and HD Helmet Camera