Try it out in a pool or rent it before you buy it. get familiar with the different types of equipment and their strengths and weaknesses. Evaluate how advanced you want to get and how often you will be diving.
Examples: BC: do you want a jacket style, back inflate, or BackPlate & Wings (BP/W)
Regulator(s): piston or diaphragm, doing any cold water diving?
Night diving? - dive light & backup
Ocean diving? - safety sausage and/or SMB, signaling mirror, dive knife and/or shears, storm whistle
take some time, read through the equipment forums, and remember that the best equipment isn't from a specific manufacturer, it is what suits your needs the best.
Good Luck!