I would go with a 2 bulb T5 set-up like this: http://www.reefgeek.com/lighting/T5...5_High-Output_Retrofit_Kit_w!_Bulbs_by_IceCap
which would be on the low end of light you need. You could then add another one or add MH light too if you want to get into stony corals later. It is good equipment and you can always add more later on if you want to keep something different later.
-chris
Needed to ask the same thing. Mine is 48" in length about 20" in depth and about 12" in depth. Wnat nothing fancy but do want shrimp and to start off with some easy corals. Please know that I am reading,reading, reading !!!Many thanks, Nancy
Depends on your desired coral stock and your budget. I would stay away from PC lighting but in a mixed reef tank PC lights is higher watts will work.
I hate to say but this isnt a cheap hobby. A 55 will raise your electric bill about 50 bucks or more monthly alone as with the price of salt and RO/DI water and test kits and food and ect. ect. . Have a child its much cheaper and will take care of itself in time.