For those of you with a GoPro...

You won't regret it, GoPro's are awesome.  I've got a Hero2.

As for mounts, the bike mount works great and you can either put it under your aero bars, or if you have a seat post that works for it you can mount it on the seat post looking forward which is a cool view.

The chest strap is the best for running.  I've never liked the head band strap because the camera's just a little too heavy for it and it always feels weird.  Plus it looks beyond dorkville. 
It's not real practical for running, but I also like using an extendable monopod with a camera mount.  You can get some cool chase views of you running or side views.

For swimming, the best I've seen is a chest strap worn backwards.  So you put the camera on your back looking up towards your shoulderblades.  This way it's out of the water and filming you swimming.  You could technically put it on a head strap on the back, but I'd be very worried about it slipping off.

If you want to put it on your helmet, I'd go with the sticky mount to your helmet.  Those things are awesome, and very easy to use versus trying to fumble with the straps on your helmet that are eternally loose.

Also, don't forget to download the GoPro Cineform studio.  It's free and you use it to do firmware upgrades and it has some good editing tools such as slowmo and other fun stuff.  I didn't find it until 6 months or so after I bought my camera and did the big facepalm.

I have the Hero3 Black Edition.   Read some gopro forums carefully... A LOT of us are having lockup issues.  There seem to be 2 main causes right now:

1. Charging from a USB port that will allow more than 500ma while charging.

2. the camera "doesn't like" Some SD cards.

It is BEYOND FRUSTRATING to have your camera lock up on you, or to not realize it has locked up, you put it away in your pocket/bag for a little while, and you pull it out and the battery is dead.

I haven't scanned the forums lately to see if there's any new developments. 

Just a l little caveat emptor.   Hey, when it's working, it works well.   Here's a couple of movies I put together with iMovie this winter:

Beijing Pinewood Derby (camera taped to the car!)

Snow Tubing

iMovie is great with these movie trailers... the kids love them!