Another wonderful approach, is to spend 10 to 15 minutes outside in a bathing suit or other dress that allows you skin to be exposed to the sunlight. This is probably best right after a bath or shower, and in addition to dealing with Seasonal Affective Disorder, acts to boost the immune system and invigorate the body.
It is also a lot less expensive than a full spectrum lighting (which is designed to mimic the light given off by the sun)