Gopro wins just about every shootout, so there's that. The black edition is worth it if you're actually going youse the extra resolution/frame rates. The silver is basically a smaller hero2... Tough to advise without knowing if you intend to do a lot of editing, or just shoot and upload. If you intend to do a lot of post production editing, the black would be a good idea. The only time I use my contour instead of my gopros is for mounting to the side of my helmet- the gopro video quality wins hands down. Better in-camera metering too.
I buy all my stuff at motorcyclegear.com, formerly newenough.