I bought a Gitup Git2 camera just a week ago, mounted it on my bike's handle bar and have been using it, both during my commute and outdoors. Great image stabilization and very acceptable quality at about half the price of any decent GoPro. As mentioned above in this thread, battery life is never over 2 hours, so that's indeed something to keep in mind.

I also wear a helmet regardless of travel distance and have a front (500 lumen LED) and back (not-as-powerful red LED) light, living under the "see and be seen" motto I still have to settle on the accoustics.