Camera alternatives for commuting (2014 version)
A few years ago we bought a pile of the sub-$20 "mini dv" cams off ebay and they work fine as safety cams. Finding a waterproof enclosure is effectively impossible, so I used a plastic bag. At ~$10 each losing one is no the end of the world. Sample video: vimeo.com/15050277. If you're experimenting, buying a couple of those might be a worthwhile start to see how much hassle they are and how much use you get out of the camera. (I no longer bother, but then I ride to Cooks River cycleway every day and only ~5km of actual roads)

One thing that I've become more aware of/irritated by recently is the difference between 60fps and slower frame rates. For a safety cam 15fps is fine, but if you want to use the video for anything, 30fps is hard to watch. And a lot of the 1080p cameras don't even do 720p60. So if you're going to spend $200+ on an "HD" camera, try to get one that does a decent frame rate. That way when you start playing with the video you wan't get too grumpy. If you shoot at 1080p60 you can usually get software-stabilised 720p60 out of it, or you can pay a bit extra and get the stabilised Sony action cam instead.