While back on a dive forum a guy had these unreal underwater reef & fish pix. People were using them as screen savers they were so good. I can't find the site again. But he had a fairly run of the mill (+/- $300) camera and a hard shell housing from this site.
http://www.waterproofcameras.com/
The housing was only $100 bucks, but was similar as some as the ones on there for $300.
That's the next set up i'm looking into, just more research to do first.
It was pretty compact too.