Lowepro DryZone 200 Backpack, Waterproof Camera Bag, Gray / Black.

Rating:
Summary: have camera will swim
Review: This backpack actually is waterproof. I litterally went swimming in the BVI with my medium format equipment safely inside. Let me just repeat that, you can literally jump off the boat and swim to shore in waves with this thing and not a drop gets in. It uses a special zipper to seal itself off, not the more common method of folding over the mouth of the bag.
Carrying ergonomics are also superb: the bag offers many adjustments and a real well-patted hipbelt, essentially like the bigger mountaineering backpacks.
This is one of those rare products that does everything right.
If you are looking for protection from water for your camera gear this is the only currently made bag, as far as i know. I do have a discontinued German model, and find the Lowepro much better (ja, obwohl ich ein Deutscher bin).
My one caveat is: if you do not need this level of protection from the elements, you would be better off with another bag, because the stiff plastic and tight zipper make it less then ideal in terms of getting at your stuff quickly.