The GoPro esn't look rediculous on your helmet. I've seen it on others, and wear one myself. It's fine.
That saidddddd, the contour ISN'T waterproof, had lower video quality (yes, it too is 1080P, but you have to get that version, and it just isn't the same quality). I've debated this for a long time myself, and after getting the GoPro HD, it's clearly a winner.
Get the GoPro, and shed us some videos!!!!