GoPros
The most popular POV (point of view) camera on the market is the GoPro. I have owned two GoPros and I have to say its the most versitile camera out there.
This is the GoPro Hero 3, It captures full HD video and even 4K resolutions, it can take 30 high quality photos in one second.
What I like about the GoPro is the wide variety of angles you can get from it, my favorites are the chest mount, and the unicorn mount, The chest mount gets your handlebars, your arms, part of the bike and the trail ahead. It captures it all. The unicorn mount is a pole that extends from your helmet and faces you. This angle can get really cool because it can capture everything you do.
This is an picture taken from my unicorn mount ^
This was taken from a helmet on the gopro
I also have many videos from the GoPro that I really like, heres a link to one of my favorites
http://www.pinkbike.com/video/371226/ This was taken at northstar with a buddy of mine.