to the OP have you noticed the audio sounding odd using a gopro?, every gopro video ive seen/heard has sounds liek the audio is canned. almsot sounding like speaking through a pipe. but not quite that bad. in most cases people using a gopro had audio recorded elsewhere and spliced hte two together. or used a good editor likesony vegas
The audio on all of these cameras (GoPro, Contour, Drift, etc.) is pretty crappy without an external mic. They use a tiny little onboard mic with tiny little access holes.
If you've got the camera anywhere that's getting hit by wind, the audio is basically unusable once you get above a walking pace. The GoPro mounting case comes with two different backs, one that's got openings for normal use and a solid one that's supposed to block out the wind better for higher speed use. It certainly helps, but when you're only improving from "godawful" to "not quite godawful" ... meh.
There are a variety of mods out there that'll help, such as simply attaching some foam over the mic, but the results are still far less than impressive.
The best option is, of course, an external mic. The latest models are coming with that option , so that's good. Unfortunately, for those of us with earlier models, the only way to attach an external is to mod the camera. Which is what I'm about to do with my Contour HD.
I've got a Countour and a Drift Stealth. I had a GoPro up until a week ago when I tossed it in to the deal for the '96 GS I just bought. the GoPro went because it's just too bulky for my tastes. Hang that thing off the side of my helmet? No thanks. Particularly not on the sport bike at elevated speeds. Also, it's not as easy to mod it for an external mic.
The Drift has an external mic port. The plan right now is to hack one into the Contour as well. I'll set up the Drift facing straight forward on the bike, with the mic run back under the tail where it will pick up the sound of the exhaust, hopefully without too much wind noise. The Contour will be helmet mounted with the mic run into my helmet so I can record ride commentary, or my last words if things go bad.

My original plan was to mount the GoPro facing backwards, but I could not find a mounting spot I was happy with on any of my bikes. I think I'll probably just pick up another Drift or the Contour with the mic jack.