NDiver - Fine Diving Gear is one of the vendors at the Under the Sea Expo and I have to say, this outfit is a lot of fun.
This set consists of:
four port tank
metal regulator with bubbles and sound
If you Lack a Diving AO, here are two recommended ones:
Sala Snook's Diving AO, with superb animations. This one needs to use Flight.
ScriptWerks:s Scuba Swimming, simple and working nicely without having to use flight.
Recommended swimming AO
Swimmer 3.0 by Michelangelo Rossini