I've been looking for something similar but more so to use when riding for evidence purposes should I find myself in a collision that's not my fault.
I've settled on this, but haven't clicked the buy button yet:
http://www.dogcamsport.co.uk/contourhd-1080p.html
Over the other bullet cameras on their site if gives:
More recording time and the option to fit spare batteries, rather than a built in rechargable only.
High quality,
Higher FPS and also alows goes up to 60FPS for slow motion replay.
Laser allignment
Other variable adjustable bits.
Option to fit your own Micro SD card up to 16 or 32gb can't remember which.
Also comes with a few mounts but there are other accesories for it at the bottom including a waterproof casing, windscreen mount for a car, or should you wish to mount it on the screen of your bike, carry case, mains charger etc.
The others come in much cheaper around half the price but as with most electronics you get what you pay for.
It was a toss up between this and the 'GoPro'. The GoPro is more of a traditional what I'd call 'camera' design where as this is more of a 'cam-corder design' so won't stick out a mile from a helmet so you'll like less of a plank. Not to mention it's around the same size as an iPhone, a little smaller but obviously thicker.