My new setup is a Canon EOS 20D with an Aquatica housing and a Sea and Sea YS-350TTL Pro strobe. SLR speed is really nice, compared to my old Canon S40 with the OEM housing and much smaller strobe. Of course, you have to sell a child to get this stuff.
I've seen people get great shots with some pretty basic Sea and Sea setups and their reputation for quality products is very good.http://www.seaandsea.com/
See them at your local scuba shop...usually.
Now, if I could just get that focus ring I need for the 17-85 zoom I really like to use...