I'd go with the GoPro, there are so many applications you can use it for aside from all things aquatic.
I've recently used mine skiing, attached to my boot, ski and my son's helmet. I've got a chest mount which I'm looking forward to using both forward and backwards on the AquaDuck. I've also got a
grenade grip to which I've attached an old camera lanyard for security, this is quite adequate for just walking around with, and a long monopod which should be absolutely amazing used parasailing on CC. These are my main mounts but I also have a suction mount for glass and an attachment to allow me to fix the camera to a bike or buggy, so I'm thinking time lapse around the MK attached to the latter. The Hero 3 has just come onto the market but the Hero 2 is a cracking little camera and with add-ons like a WiFi pack you can remotely control and view (with a 3 second delay) what the camera sees from up to 200ft away.
Try not to look for a camera that does too many things. I've an DSLR with a myriad of lenses from 10mm up to 270mm, a Panasonic Lumix for quick shooting and HD video and the GoPro for pretty much everything else. Just have a look on
youtube at all the things you can do with it