I've been following Peachii's advice about the flourescent bulbs, and it's worked really well for me thus far. I believe I got the highest wattage I could...so the CF equivalent to a 100 watt? I've got several low light plants, but also some red ludwigia which is a higher light plant, and they're all quite happy and growing well in this setup.
I purchased two of the desk-type clip on lamps they carry at walmart, each was about 7$, the neck bends and the base clips onto the side of the tank. I bend them so that they're right over top of the water, and clip one to each end of my 20g long tanks. For the cover I got a sheet of plexiglass and cut it to fit, I love the way that looks, cleaner, simpler, just overall a better look in my opinion as compared with the old black hoods. You can get glass or plexi at most Home Depot's or Lowe's stores.