Personally, I'm getting the old mountainbike ready for outdoor winter riding where possible. The roadie will go on a trainer stand for those days I can't get out! The game plan on the trainer is to do interval sprints through the commercials and recovery pace through the program when I ride the trainer.
Cold weather riding can be fun though, especially when the roads get a little slick. Watch the sweating thopugh, hypothermia isn't too far away if you dress too heavy or too light or you push too hard. Caloric burn is higher as well when the weather is cold. Higher air density and working and burning calories to stay warm at the same time!