I've been riding a '95 Cannondale hybrid in the winter in Minnesota, putting on 17k miles in that time. I've had some problems with frame corrosion, bubbling the paint. It's been easy to take care of: scrape off the loose paint and corrosion and paint it with Rustoleum metal primer and black gloss paint to match the original, with quite good results.

The main functional problem area of corrosion has been the valve stem hole corroding enough to prevent non-destructive removal of the valve stem. Fortunately, I had my patch kit along the first time I ran into this problem and successfully got the flat fixed. I should be a little more diligent about keeping the hole cleaned up, but it's easy to forget about it and...