A helmet mount will remove almost all the vibration, and replace it with video of you moving your head around -- which may or may not be a good thing for your purposes.
If you can mount it to your frame rather than handlebars you'll get less vibration. I've got one mounted to my seat post facing backwards and that works very well -- but it does still record a lot of vibration sounds.
As for the mounts, there's some aftermarket ones that are made of metal and look nice -- I've had the stock mounts fail. That said, I'm still using the stock mounts and they're mostly fine. I noticed recently that Deal Extreme sells GoPro mounts for a good deal less, and some are metal -- don't know how the quality is, however.