I keep SPS and some LPS such as chalice and mycedium, some favias, frogspawn, torches (pink and green), candy cane, and trumpets. But mainly SPS and i try to focus on corals with nice colors and color combinations. All different types of acros, stylos, millies, montis - branching, encrusting, and plating, etc. etc. Probably forgetting quite a few as well. My main display is a 180 with a 20 gallon frag tank attached to it and a 10 gallon fuge as well, also have a 120 with a 25 attached to that. The 120 system houses softies - zoas, rics, palys, mushrooms, leathers, etc.
I run eight strips of powerbrites on the 180 and its a psychedelic light show at night before I turn them off. It's not your typical reef of yesteryear. Most of my corals I order and have them sent in or I occasionally cherrypick local stores and buy and trade with other collectors in the area.
Great thread, looking forward to the other replies!