I have, and like, the
Olympus Stylus 790 SW ( I paid $299) -- two years old, waterproof to 10ft, 7.1 megapixels. Works great in good light. Video also capable under water, with sound. Can take much wear and tear. Also advertised as sandproof, and mine has proven to be pretty good, covered in beach sand, as well as being dunked in salt water -- just be sure to follow manufacturer's simple suggestions on cleaning after use in water.
Newer version is the
Olympus Stylus 1030 SW -- maybe a year old, waterproof to 33ft, 10.1MP.
Newest verisions:
Olympus Stylus Tough-6000 -- waterproof to 10ft, 10MP. Retail $299 (can find cheaper and look for July 4th Sales)
Olympus Stylus Tough 8000 -- waterproof to 33ft, 12 MP. Retail $399
All are very resonably priced and fit nicely into pocket, so that you will always have it when you need it.