Kevin, welcome first of all. As for lighting there are many fine comparison guides available on the internet. You will find some good information here or at some of the other fine reef keeping boards.
In short a summary:
Metal Halide - High penetration, draw fair amount of power, expensive initially but arguable cheaper over the long run. Has that nice shimmer effect. A must really if you want to keep many clams, anemones, and some stony corals. Usually consists of a
socket and reflector attached to a remote ballast. The bulb is attached and the fixture can be mounted in a canopy or a hanging pendant. They produce copious amounts of heat. There are many variations on the basic halide rig - do some reading.
Power Compact - Relatively affordable, many many configurations to choose from. Moderate power draw and heat. Can be worked into all kinds of configurations. Not as much punch in deep tanks IME. Fine for shrooms, soft corals, some anemones and stony corals if placed near enough.
Normal Output - not really an option in most tanks with corals, you will be pretty much limited to fish and maybe some mushrooms and polyps. Cheap and can easily be used for supplemental lighting with other fixtures.
VHO - What I have. Basically flourescent on steroids. High output, decent color - a little pinkish sometimes. With adequate coverage you can keep many stony corals and some clams and anemones. Drawbacks so far is bulbs don't seem to last as long and are comparitively speaking expensive.
There are some newer interesting technologies like T5 bulbs and LED lights but so far they are expnsive and not readily available.
Also figure out tank depth , distance of lights from water and what organisms do you want to keep. I suggest buying more light than you need , trust me it's a lot cheaper than retrofitting everything later on down the road when you find out your light is inadequate for a specimen.
