I just want to mention the Cressi Archimede computer, as something worth looking at. It goes for cheaper than many others around here, and I have had nothing but good experiences with it. One thing I like over (some? all? Haven't had all...) Suunto's is, that the display is nice and big. Does Nitrox (up to 50%) too and is quite easy to use. It also seems that the Archimede is less conservative in NDL and deco times than the Suunto, but I have not brought them both down at the same time to compare.
The algorithm is supposibly: "Bühlmann ZH-L8 algorithm, redesigned by Randy Bohrer to make it suitable for a more sophisticated RGBM program"....
(Of course, bigger display means that the whole thing is bigger than the suunto....apparantly attractive to octopusses, which on occation have grabbed on to the computer and kept me company for a while on dives in the mediteranean...)
Ohh..and writsmount is definitely the way to go, regardless of which computer you choose.