Choosing a community tank.?

55 gallon for sure. Get some guppies going, and let them breed a while. Put some barbs, maybe swordtails, neon/caridnal tetras, possibly a couple dwarf ram cichilids and anything else you find interesting. Get a pleco, or even a few smaller bristlenose plecos to help with waste and algae, as well. Stalk your local pet shops to see what they carry and go from there.