Whatever takes you fancy. But keep in mind that $200 isnt a lot of money if you still have to spend it on filters heaters etc. Is the tank cycled withg water and good to go?
If it was my choice, I'd buy 2 oscars, a baby red devil, a gibbiceps and maybe if I had enough money a 5" jardini and 3 chinese algae eaters to munch on algae...