I'm definitely gunna start using some sort of Loctite (or something similar) for "seize protection" on my wet day bike, because grease -- even marine grease -- eventually washes out. I recently rode a hard 45km in heavy rain with tons of road spray, and came home to find that most of the grease had gone from the threaded parts that were subject to the most 'abuse' from the weather (pedals, BB, etc). I ended up undoing and re-greasing almost every bolt on the bike, except the levers. I even rebuilt and re-greased the hubs and all the bolts on both derailleurs.
Man, there was water everywhere!! Not only inside the frame, but even on the axles in the middle of the hubs (old Shimano: cup and cone). So, I'd like to rebuild the bike with something better than grease.
I did some work on a friend's old mountain bike, and it was one of the most trashed bikes I've seen. The cables housings were damaged and barely holding the cables, which were frayed. The sealed BB axle was a bit wobbly. The cog and chainring teeth were the sharpest (worn) I've even seen -- and there was lots of corrosion on the frame.
I assumed I might not be able to get the BB off, but not only I could I get it off, but the threads on both the BB and the frame shell were totally pristine, due to the cream-coloured powdery stuff on there.