When I first got involved in this stupidity in a serious way my weapon of choice was a Nikon FM usually paired with a f4 Nikkor 200mm with HP5 and, if I was lucky, a roll of Fuji for colour prints. This combination served for many years through all that was thrown at it ( sometimes really thrown ) including soakings, being dropped , banged and generally abused.They never missed a beat - from Thruxton to Oulton, March to October year in year out. I now have a Nikon D300 and a selection of lens including the original f4 200mm but am so wary of all the gubbins inside that the weather forecast is closely checked before venturing out. I have no doubt that Nikon is sealed properly but I am scared to find out just in case...
On a slight tangent I heard on Radio 4 the other morning that 10yrs ago in London there were 280 professional darkrooms in London now there are only 8 .
I never had any problems at all with any of my film Nikons, 20+ over as many years, I still have three of them, but that's why professionals like them of course, though I did once drop my F4, which needed a new viewfinder top moulding, that camera and our D300s all have cast magnesium bodies of course. A year or so ago, someone dropped my almost new 12/24 f4 Nikkor. It landed end-on on a hard floor, pushing a filter right into the outer ring, breaking it quite badly, though everything still seemed to work OK. My friendly local Nikon/Canon repairer does a lot of sub-contact work for Nikon UK, he's there almost every week, so after fitting a new ring which cost £75 in all, he took it with him to check on their high-tech equipment, absolutely perfect, no internal damage at all, and it landed with quite a bang. He told me that in his experience Canons are rather easier to damage, though there isn't a lot in it, and he never has any trouble getting spares for either, which is one of the things you're paying for of course. Next time I see him, I'll ask about their weather resistance, though I suspect they are less vulnerable than we think, Nikon claim that they're well sealed and protected in that respect.
On that professional darkroom thing, it was on Radio 4's Front Row midweek, five minutes or so, worth catching while it's still there.