I use 6 4 ft. fluorescent fixtures. That's 480 watts total, I think. So much light is necessary since the lights are 3 ft. above some of the shorter plants. There is a small terrarium for seedlings and small true highlanders that can't tolerate major condition flucuations. Right now it's just Drosera seedlings.
I did seal the wood with many, many coats of polyurethane. Even so, I may have to refinish again sometime. It is a homemade tank. There is a plexiglass covering between the tank and the lights. I have removed the ballasts from several fixtures to try and minimize heat transfer, but the tank is so large that heat isn't much of a problem.
Thanks for the compliments, everyone!