Good idea Mike, possibly worth putting up as a sticky?
I have an Archos 404 hard disk recorder (
http://tinyurl.com/m8bld) with the matching Archos helmet camera (
http://tinyurl.com/23a52j).
This was an upgrade from my ATC-2000. Nice piece of kit with an improvement in the video quality whilst also being better at videoing at night (I will post a video of this when I get a chance). The field of view is also better than the ATCs. It is also nice that I can review the videos instantly without having to download them to the PC. This saves a lot of time and effort. It also has a time stamp which is great if it will ever be needed as evidence.
There are of course some issues. It is recording to a hard drive and occasionally the data gets corrupted as it writes, although so far when I have tried, I have managed to repair the files. The battery is not the best and can't be removed from the case (It can on the more expensive 604, I'm not sure about the 504). My commute is 20 minutes and the battery can just about record 3 journeys (60 minutes).
I am however very pleased with it, although I believe that Archos are no longer selling the 404 and are now marketing the 405 which works with SD cards and not a hard disk. This might be better suited to recording commutes as it may be more robust. Who is going to be the first person to try it?