You definitely want to read up on breeding before making any decisions. I suggest you check out this for more info on breeding. Depending on how fast you want to get into breeding you might consider picking up some proven breeder normal females and a nice male, if you are looking to start breeding in a few years you could get hatchling female morphs. Males will breed much sooner than females, so you want to focus on females originally.
I personally prefer to have females that are co-dominate, i.e. pastels, fires, yellow bellies, butters, because you can either get super forms faster by breeding a male of that morph to the female or by breeding a son back to the mother. So for instance if you wanted to start with a spider and pastel, I would get a nice female pastel and a male spider. That way if I get a male bee I can breed him back to mom for super pastels and killer bees. If the dad was the pastel you need to wait for a bee daughter to grow up before you could try for supers.
As for what to get, it really depends on what you like. If I was just starting out again I would get a male bee, female pastel, female lesser/butter, female yellow belly/fire and a female enchi. One male can easily breed multiple females so you don't need a lot of males in your collection.