DSLRs can give you amazing quality but they are a real pain to carry around and cost a lot. You'll also need to pay for image stabilized lenses if you want to have a chance of shooting without shake. This all adds up to a serious amount of money.On the other hand, nothing beats a DSLR for image and video quality once you get the hang of it.
I have the 5D mkII and you need some serious computing power and memory to work with footage from it. The 7d is much better in that it uses more conventional frame rates which makes editing a lot easier (but will never give the depth of field and low noise performance of the 5d mkII).
My personal suggestion would be something like a Casio Exilim HS10. Its a point and shoot but you can manually adjust a lot of the settings. The lens can be stopped down to F3.2 too (great if you want to blur out a background to make the subject really stand out or if you're shooting in low light). It shoots HD but the big selling point for me was its high speed mode. Fun to watch and great as a training tool. Here's a slo-mo clip I took at the London Freeze:
Considering that I was hand holding the camera (I did brace my arm against a pole to help), it was dark and that the light conditions were so variable I was pretty impressed by the quality and lack of noise of the video produced. I did need to manually set the aperture and ISO but left everything else to the camera. I've got some more clips on my profile. There is a vid from woodward which looks a lot noisier and less sharp. Thats from the previous generation of these cameras and there was little in the way of manual control. You can see what a big difference being able to manually control some settings has (the new camera has a better low light performance sensor too)
Go-Pros and Contours are great as helmet cams but can't match a basic point and shoot for normal hand held photos/videos. By the way, don't buy the Contours; they fall off the whole time (I've spent a lot of time looking for mine, even the safety leash comes off with a moderate impact). I have both the Contour HD and the GoPro HD, GoPro winds hands down for skiing.
