29 gallon I am assuming is 30LX12WX18D.
I am a HUGE fan of T5HO lighting. I have tried Metal Halide, Compact Flourescent and T5HO.
If you want corals, you'll want one of these three. Power Compact
(click the word for a link) have a good output for the power they consume. T5HO
lighting usually doesn't offer as much wattage as PC, but you have more options because of the amount of bulbs. You can use different combinations of bulbs in order to achieve diferent colors in the tank. You can usually buy units with 6 bulbs, but not many are offered in the 30" size. Metal Halide
are by far the most expensive to buy, run and maintain. They run hot, the bulbs cost anywhere from $65 - $100, and they usually require external ballasts to run. The ballasts are sensitive, and if they get dropped or knocked around, they malfunction. You can usually turn your heater down if you are running MH. They do put out the most brilliant
light of any fixture. These lamps produce the best Ultraviolet Light, which is neccassary for coral growth.
With all that being said, what kind of corals are you planning to keep? If you are starting with Softies and some LPS, Power Compact or T5HO are a good lamp. If you plan on eventually going SPS, then I suggest Metal Halide. Water Quality is a very vital parameter in keeping Corals. Your pH, Nitrate, Magnesium, Calcium and Alkalinity must all be within good levels. You can read more about this here
I personally keep LPS, softies, crabs, snails, a clam, shrimp and two anemones in my 150 gallon reef, under a 12 bulb Nova Extreme Pro T5 unit. I am happy with its light output.
You can also check ebay for units. I bought my unit from my LFS, and would've saved a few if I ebayed it...