If this is a relatively small tank, using CFL (compact fluorescent) bulbs can work very well. I have two of these (9w CFL daylight 6500K bulbs) over my 10g and 20g (the light fixtures take two incandescent or screw-in bulbs) and the plants are thriving. Over larger tanks, where it would take more bulbs, they are less desirable as fluorescent (tube) lighting or LED would be much less expensive in operating costs and be more effective with respect to light intensity (brightness).
If you already have the fixture then CFL can work; if you are looking to buy the fixture, and depending upon the tank size, fluorescent (tube) might be a better choice. Or LED.
A timer like the ones sold for lamps is a good idea with fish tank lighting. A regular period of light/dark is better for the fish and the plants, as light does affect their circadian rhythm and may cause stress to fish. One also has to find the balance of light/nutrients that will suit the plants but not encourage algae, and while adjusting the duration can deal with this, the initial intensity and the plant species/numbers and tank size all factor in.
Byron.
