I don't know what everyone's talking about... An incadescent bulb has the exact same possibility of electric shock as a compact fluorecent bulb, which comes standard with these things. The important thing is the metal part is competely covered by rubber or plastic, which is part of the ballast for incan. hoods.
The important thing is not overwatting your ballast, but most hoods tell you the maximum watts to use, and with CF, you should be fine, as they use less watts than incandescents.
I've kept an incandescent hood over a ten gallon, and like Seleya, I use compact fluorescent screw-in bulbs with no problems. It's the only way to go with a planted ten gallon. Been up and running for more than a year now. Glass between it will eliminate some of the lighting your plants will get.
MOS, I wouldn't worry about it. Why would complact fluorescents cause a problem when exposed incandescent bulbs wouldn't?
If someone thinks this would be an issue, could they please explain why?
In the saltwater side of fish keeping, we keep lights over water all the time. Sometimes with a plastic shield, sometimes not, but in that case the lights are placed higher above the water.