With the record temperatures here (short sleeves in October? WTF), it doesn't seem like winter will ever come back. However, it is impossible to ignore the fact that it does get dark earlier and earlier. Princess of Pink has some great suggestions for preventing SAD:
http://princessofpink.typepad.com/princess/2007/10/changes-in-atti.html
Check it out. How do you deal with lack of sunshine in the winter months?