Contour discussion forum has advice from Contour Staff that Class 4 is fine.
http://support.contour.com/contour/topi ... equirement
Wish I known 'cos I got class 10!
Centre.com have 16Gb Kingston class 10 micro SD for $26 or Class 4 for $20 which is hard to beat.
I'm using the flex strap on the headset. Very good video except for annoying rattle from rotating mount itself. Many users have made same comment and solved it with super glue which makes it a fixed mount. Not really an issue to dedicate a mount to a bike they are available from evans at an almost reasonable cost
BTW it is understood that Nokia battery BL-5C is a perfect match for the contour battery and is much cheaper.
I had a near miss last night and was really looking forward to getting the clip off the camera - especially as the aging merc driver was on the phone. Major disappointment then to realise that I'd failed to set the camera to record!
Enjoy the ContourGPS - while not perfect in every way (on-off button) it is a fun toy!
Michael