Some good mounting options have been created by K-Edge, and have since found their way onto ebay with cheap imitations - which realistically probably work in exactly the same way at a much reduced cost.
The black one is for mounting off of the seat rails and works well - I use it:
The silver is a handlebar mount - never used it so I can't comment:
The red one is also a handlebar mount that I do use - its quiet good, but if you move your bars around a lot, it can become a bit hard to watch:
Personally, I find having something in the image that is stable and consistent helps the footage at viewing time (wont make you want to vomit). For instance, a helmet mount on the side of the helmet so you see the helmet always in the image, or with the k-edge rear seat mount, the back wheel is always steady and constant. Makes a huge difference.
For comparisons sake, and to give you an idea, here is a video I shot using the the GoPro chest mount, K-Edge rear seat mount and the k-edge handlebar mount (the read one in the image above).
[video=youtube_share;DmBFyc_lxSc]http://youtu.be/DmBFyc_lxSc[/video]