A triton bulb (the one I mention above) will be great and last longer than most bulbs (phosphors don't die out as quickly). You can use it effectively for about a year. Of course, it will continue to shine after that. It'll cost you a pretty penny, though.
If you're looking to boost light levels, you can just buy the most standard aquarium fluorescents you can find... They'll work, too. Generally ppl advise fluorescents in the 5000-6500K range, or the 5000-10,000K range (warmth of white light).