I've heard of people installing sealed cables to keep stuff from freezing in the winter, though I'm honestly not entirely sure how well they do or don't work -
http://www.gore.com/en_xx/products/c...eon/index.html (Gore Ride-On Cables)
Seems like a good idea...I personally have an internal hub, and other than getting slow for shifting in the winter sometimes hasn't been a problem. (Though I'm not really suggesting you buy a whole new bike for it or anything)