Riding indoors sucks. I usually keep it reserved for March , short specific rides to build up speed up to an hour. Specific DVDs help to ride indoors fast. I could not watch a movie while riding indoors-too boring and too slow to benefit from it and I usually stop riding in the first 15-20 min. I like riding outside even in winter(upstate NY).
What helps me to stay motivated riding in cold winter months is usually some planning. Buying new cycling toys to see how they work and test them in winter helps , it may be new gloves or studded tires, fenders or new light or new winter jacket or base layer,etc....
Also it helps to find somebody to ride with and plan rides together. You can even post a note in your LBS to find a riding partner to ride with. Many people loose motivation to ride during winter, unless there is somebody out there doing it, so they will join you.