Like other said - I ride my hybrid/cross when the roads are sandy and salty - and in NY they get pretty sandy and salty. Also - they're a little easier to handle in gravely conditions. When that stuff is pretty much gone, my pretty road bike comes out. Lately I've been switching back and forth because of some crazy weather conditions.

I wash my by bikes with some dish soap and warm water. Rinse with water (never water pressure directly at the bearings, though) - make sure the chain is clean and then re-lube. The extent of the wash depends in the road conditions - salt always warrants at least some wipe down/wash for me.