I have my camera, a Sony FDR-X3000, mounted on the top of my helmet. Mainly because that camera comes with no way to mount it. The camera has a 1/4x20 tripod socket on the bottom of it, so you can mount it on a tripod, and it comes with the male part that snaps into the flat part that glues to your helmet, but it doesn't come with the flat part that glues to your hemet. I tore all the boxes looking for it, but it is not included. What a bunch of crap. So I had to go back to the store to buy the side mount, to mount it on the side of my helmet, but they didn't have it, all they had was the flat mount that goes on the top of the helmet. So I got that. I kind of like it now that it is on top.
I remember when I got my first Gopro years ago. It came with a lifetime supply of stick on mounts, all kinds of right angle adapters, a bicycle helmet mount, a head strap, and a suction cup mount!