I have an incandescent hood thingy.2 Normal light bulbs - 13 watts each.
i think it's medium. it depends on how large your tank is. if it's a normal 10 gallon, i think it's adequate for most low light plants. I have a 10 gallon with 2 cfl (compact fluorescent light bulbs) and I think it's fine for most plants.
Those bulbs Dan suggested are the bomb, even though they are pricey. Walmart sells a copy of them, that is in a slightly different spectrum, but they run 4 bucks each - I still manage to grow some nice crypts, fernleaf javas and anubias with them though. Really like them - besides, the incandescents throw off too much heat, and then the water temp changes a lot over the course of the day, which eventually makes the fish more prone to disease. Seriously, you'll dig the compacts.
That would be adequate for low light plants like Java moss and Cryptocorynes. Compact florescent (twisty) bulbs are good replacements in an incandescent hood. They are cheaper to run, produce more light, and emit less waste heat. That heat from an incandescent bulb can damage or even melt plastic near it. See if your pet store has Coralife bulbs. They come in 10 and 20 watt. Even the 10 watt will produce much more light than the 13 watt normal incandescent light bulbs. If you don't find them locally, they are available online from sellers like Aquarium Guys, Big Al's, and ThatPetPlace.
