Looking for a decent, tough, all purpose camera to take along on my outdoor trips. Waterproof is a must as I spend a fair amount of time on and around the local rivers. I know little to nothing about cameras but I need something that will occasionally get dropped in some mud, rained on or float a ways down some rapids. I'm not looking to spend a great deal but could go maybe $400-500 unless something just as good can be got for less. Any suggestions would be greatly appreciated.

Thanks,
John