You should do discus. When you upgrade again to something like a 150g, consider a fahaka puffer. The are awesome.
I have 4 tanks in my house, but only 3 running. My goal: When my husband and I buy a house we will be looking for one with a decent basement to turn into a massive fish room for breeding angels, rams, bettas, not sure what else yet. I have basic plans made up that I am constantly adding different ideas too, but can easily be changed around to fit the specific space we find. It's still a few years down the road though.