If you're asking for advice between the Hero and the Hero2, they are both great, but the Hero2 has some nice extra features like higher mega-pixel photos, external mini HDMI port, external mic input (in my line of work, this is helpful, maybe not so much for trail use, though), a bunch of wi-fi options, live streaming, way better user interface (imo), selectable frems of view (wide, medium, narrow) and some other things. I love my Hero2, but I also have to Hero's in addition.
If you are asking the difference between Hero2 motorsport, or Hero2 Surf or Hero2 Naked, etc. They are all the same camera, just different mounting types. I basically just bought all the mounts that looked useful for my purposes - helmet, chest, wrist (was awesome for snorkeling) roll bar, handlebar...I have yet to use the suction cup mount that came with my original Hero. I have the tripod adapter attached to a vice type mount that has a swiveling ball on it (found on Amazon). VERY useful.
They are fun cameras. I'd, personally, go with the Hero2.
Edit: don't bother with the Hero 960. It's not true HD (1080).