Mikey, and others,
Yes, I used grease, but not the marine grade type that Bo mentioned. I thought I had repacked them before the 2012 season, but maybe not. My headstock bearings are much more susceptible to this kind of damage because although there is a seal at the top and at the bottom, the headstock is open and salt plus washing water enters from within where there are no seals. On my wheel bearings, I have removed the inner seal, but left the outer one in place. If I spin my rear wheel by hand (without the chain), it will still rotate for up to 10 minutes, so I believe the seals are effective. The other most affected part is the chain. Remove it, wash it in solvent, then wash it at least twice more in soap and hot water, then again in solvent or WD-40 (better) and finally oil it and store it in a zip-lock bag. Polished aluminum seems to hold up OK, but raw aluminum pits almost as badly as raw steel. A good paint job on aluminum and steel also seems to hold up, but you have to clean and inspect it, because any scratches will start to breed rust. Some stainless steels, probably marine grades are good, but cheaper grades also come back with a haze of brown on them. High strength bolts rust faster than lower grade, in spite of the nice gold finish they apply to a lot of them. The only sure way to keep everything clean is to disassemble, clean, and wax or oil it. Look for cracks in the frame while you're at it!
Tom