The OP is asking very specifically about the benefits from a rigged traditional cam to a GoPro.
Buncha' (3)posters start talking about getting a Contour HD. I Talk about the benefits of a GoPro HD vs the Contour HD.
Buncha' (2)posters start comparing two very different levels of technology and lament how much better an HD Contour is compared to a REGULAR GoPro (200 dollar price difference).
Since no one else will answer the OPs question. I will.
Go with the GoPro if you can find a use for it later. It will take standard 5MP pictures so you can use it as a regular digicam... limited, but you can.
Although a good $2-300 Digicam that has a 720p video recording mode will be very good actually, but you will need to buy a good stable screw-type camera mount made for mounting traditional cams to handlebars.
This way I can use the camera on my summer vacation, get much more use out of it in general and have an easier time justifying the expense.
I believe the latter is your best option. The video quality will be good and obviously its gonna take better pics than the GoPro and actually capable not like the Contour
