I only have 28 different plant types because they are split between 8 tanks.
I prefer to have about 4 or 5 different plant types as opposed to a mishmash of plants from different areas, but that's just me. Also by keeping biotope type tanks (I'm not super strict with it), it helps me choose what I will keep in each tank.
Basically I have a South American and a West African tank and the others are smaller so I borrow plants from each tank and add most of the plants that I like from Asia there.