I've got a Pentax Optio 33WR that I bought when they came out. I figured it ought to hold up to the dust where I was heading as well as be usable on my kayak when I got back. So far it's survived a year and a half in Iraq, getting bumped around in the truck and while mountain biking and numerous splashings while kayaking (including being dunked on more than one occasion). The picture quality is decent enough but certainly not pro quality. The downside is terrible movie quality, short battery life (luckily is uses AAs), limited actual zoom (I pretty much refuse to use digital zoom), and only 3.2 megapixels. I'd say I've gotten my money out of it though.
I've also got an Olympus C5050 with the Olympus waterproof housing for it. It takes good photos but it is very bulky when it is in the housing. It's also not super durable, I had to send it back for repair after I dropped it and the lens refused to come out. They had good warranty work though and I got it back quickly.