I discovered a name for my winter doldrums a few years ago. After reading up on S.A.D., I purchased a couple of Verilux Happy Eyes lamps for my office. I also changed most of the light bulbs in my house to natural spectrum bulbs. Recently I bought a "Sunshine Simulator" from the same company. It seems to help. I don't feel as blah, bored, listless, restless, etc.
http://www.verilux.net/