I was gonna buy one today but forgot my cash at home
Either pole or helmet. Helmet seems most common as you wont need to carry that pole around all day.
I have been looking into the 3rd person mounts. This looks very cool as well and should give some pretty cool vids. Check some of them out on youtube.
The Micbergsma guy is one I just saw last night using the 3rd person. I'm sure I could make something simple and will give that a shot before I spend money on a rig
Tip: I'd add a small leash/cord to the GoPro that way if it pops off with out you knowing it will still be attached to your helmet and not lost for someone to possibly find in the summer