I bought a new, larger digital SLR with some good lenses this year and got a big Pelican case for it, then discovered that if I kept it in it in the case it would be virtually inaccessible for any photography while paddling.  No good, as far as I am concerned.  I don't take my camera on a canoe trip to have it in a case under my seat.

So. . .it ended up in its soft camera bag in a SeaLine dry bag where I could pull it out and take pictures.  I probably should mention that all of my photography equipment is insured against all disasters with a special rider on our household insurance.  

I still use a waterproof point-and-shoot on really rainy days, but otherwise I go ahead and use the SLR in the canoe when the spirit moves.  The dry bag is cumbersome to portage--a backpack would be easier (I have one for photo excursions when I am not in a canoe) but that would result in triple portaging and we aren't there yet.   ;)