your lighting will determine what type of corals you can keep. If you are only interested in soft corals, LPS, and polyps then all you need is a PC or VHO set up with a mix of 10,000k and 03 actinic (blue) bulbs. both of these are good and everyone has a different opinion on the PC vs VHO preference so just choose the most economical or the one you prefer to look at the most. If you think you may want to keep SPS, or clams then you will need to mix in some MH (metal halide) lighting with either VHO or PC for the actinics. This is probably the best (but most expensive) way to go as then you are not limited on what types of corals you can keep. Do a search for more info and look on the internet for places to buy and save some $$$ over buying from a LFS.