The HD Hero2 quality is fantastic, but I've decided to go with the Contour Roam. I don't wear a helmet, so my mounting options with the GoPro include the headstrap (which looks ridiculous) and the chest strap, which is definitely more skier-orientated.
I'm going to grab the goggle mount for the Roam and use that. I don't think I'll have much stability issues, and if I do, I plan to tether it to the outriggers on my Oakley Splices to give it a bit more stability.
If only the GoPro had a better form-factor and I'd be all over it.