I feel your pain. I dropped an ammo can in the Middle Fork Salmon a couple years ago. I went to grab my iPod to listen to some tunes. I thought I had two straps, but there was just one on the handle. The second I hit the cam buckle, the box dropped like a rock through the middle of my cataraft. It had my iPod, wallet, tools, spare parts for the raft, flashlight, toothbrush/paste, deodorant, ibuprofen, and several other things. It also had my keys. I just got a new car about 3 weeks prior, and it only came with one key. Luckily, I had 2 spare keys made the day before the trip. Unluckily, I left those new keys at home in the chaos of packing everything. I had to borrow a truck from one of the guys on the trip, drive 3 hours to Stanley where my wife met me after her 3 hour drive from Boise. I got a key from her, then we each drove back 3 hours. I slept a couple hours and then woke up and drove the 6 hours back home.
Lesson #4: Keep your important items in a secure location. I now have a pelican case that fits very snugly in my frame and has extra straps to ensure it never drops into the river.
Lesson #5: Keep backup tunes in your car. I was using my iPod, but it's now in the river. There was no radio for the majority of the drive. BORING.
I also keep one of these on my camera now: Olympus Floating Foam Camera Strap - 202204 - Buy.com