I need a full-spectrum happiness light. Suggestions?

I've officially decided it's too cloudy in New York City. Denver spoiled me with sunshine.

I'm not leaving—not even close—but it is time to get one of those full-spectrum happiness lights to ward off SAD (Seasonal Affective Disorder).

Has anyone tried them? Any particular brands or specs or whatever that I should be looking for? Is a used one OK?

Thanks.