If you intend to use it as your primary camera, and want the highest possible quality and control, I'd recommend looking at the new Panasonic Lumix TS1 (28-128mm optical lens, real lens-shift image stabilization, waterproof to 9 feet, shockproof from 3-4 feet, around $350) or the Canon D10 (35-105mm optical lens, real lens-shift image stabilization, waterproof to 30 feet, shockproof from 3 feet, around $300). Both of these will likely excel a bit with regards to image quality over some of the less expensive waterproof compacts, because they are essentially 'midrange' compacts with waterproof shells, as opposed to cheap compacts with waterproof shells. And they both feature mechanical image stabilization, as opposed to the more common digital stabilization. Also, the Olympus Tough 8000 and Pentax Optio W80 might deserve mention in this class, as the Olympus also has mechanical stabilization (though not the Pentax) and both have a useful 28mm wide end for around $300-320.
If you want to pick up a cheaper camera that can give you the underwater ability for a bargain price, check out the Fuji Z33WP, Pentax Optio W30, or Olympus 1050SW. All should be found for around the $150-160 range, and all can do at least 3 meters water resistance. The lenses all don't have mechanical stabilization, nor do any have a true wide angle lens (they range from 35mm to 38mm at the wide end). And they all may not have quite the quality lens as the higher priced models. But they're a bargain for the money. Personally, I'm thinking of picking one of these up myself just as an extra fun cam for underwater stuff - my Sony T100 remains my primary compact, and my DSLR will still do the bulk of the serious work...but I used to have a waterproof case for an older camera, and miss the ability to walk around in pouring rain snapping pics, or jumping in the ocean or pool with the camera. Personally, I kind of like the Fuji - it's very small and thin, fits in a pocket well, and is a good bargain...but that's for someone who has 2 cameras and is just looking for a cheap third one to abuse!