I've been eyeing this one up:
Oceanic Geo Wrist Computer, Dive Watches, Oceanic, Oceanic Geo Wrist Computer
It's got nitrox, user replaceable battery, backlight, and it's a pretty good price. It also has a small form factor. It is about the size of a large sports watch, instead of the big hockey puck sized units. My girlfriend dives this computer and she loves hers.