Satin Hands from Mary Kay is great stuff! You need to treat your hands with that every day or two through the winter. Since I started using that, I no longer get cracked thumbs! I do apply lotion every time I wash my hands through the day.
For treating cracks, Neosporin Plus works great---I put it on with a band-aid at night and all is well by morning. The Plus part of Neosporin Plus is a topical pain reliever, and it really helps if you get those cracks in your skin.