Just wanted to chip in a vote for the OJOcam, or the Mini 0801 as it's more commonly known. You can get the version with GPS for less than a hundred bucks. My only gripe with it is that it can be picky about which microSD card you use - I have a Samsung Class 6 work fine, but a Class 4 and a Class 10 from the same line that do not.
http://dashcamtalk.com/mini-0801/ for more information