lots...
I have most of them, i use the suction mount the most, on my board with an evilbay helmet arm, around the helmet arm i put a piece of pool noodle (yellow so it is easy to see) and will float the whole lot. the floaty back door only floats the camera and will sink with most mounts attached. The arm also gets the camera up a little higher for a better shot.
ive used the head mount but you cant use floaty back door as the camera wont tilt up enough..
handle bar mount is good on the paddle gives great shots but throws the paddle out of balance its ok when you get used to it.
I havn't stuck a mount to my board or paddle yet (i have the surf mounts and black ones) as not yet sold on a permanent mount.
I think you need a fail so you wouldn't tear the deck in a stack/bail out.
I had the suction cup come off once when my board and another board slide deck grip to deck grip in the surf and knocked the camera off.
And my old suction cup (gopro one) snapped in the surf the small plastic part behind the silicon cup snapped leaving the cup on the board and top half on the deck.
using the chest mount makes you violently ill when watching your vids,
i have bought this
www.rammount.com/to glue onto my inflatable as there is no other choice.
Ram mount do a pole mount sort of thing that could rival dj's downwind mount
www.rammount.com/NewProducts/RAMExtensionArmKayakCameraMounts/tabid/4637/Default.aspx#/but all ram mount stuff isnt cheap
what you use will depend on what your doing and the risk of loosing the camera.
hope this helps