After many years using various Olympus OM models - I only broke the OM3 (a fully mechanical camera) which although it dried out OK after total submersson in Taly-y-sarn Quarry drainage tunnel, the drop onto the rock killed it. I then moved over to Canon. After a few years with an EOS 1V I took the plunge and bought a sec/h EOS1D Mark IIN. Heavy as f*&k but takes brilliant photographs. ISO 50 - 3200 (eqv). The nearest similar camera reviewed above is the 5D which will give a better image (Mk IIN is only 8.5 MP) but the Mk IIN is a professional build and is bomb proof, it gets wet and muddy and I just wipe if off with a damp cloth.
I also use the 17-40 mm lens but with the smaller sensor the equivalent focal length is 22 to 52 which I find ideal. The sensor stays very clean. After about 30 U/G trips I have still to clean it.
I take the view that a camera is only for taking photogarphs. When I'm old I want to look back on some good photographs rather than have a clean camera in the cupboard!