Thanks for the advice guys.
What I am gathering is that my options are either:
1 Oscar
or
2 BPS
When it comes down to it, which choice will be more entertaining for my three year old (me too!)? I dont want a fish that is hiding/sitting still the entire time. I have observed both in the LFS but with such small tanks I really cant seem to judge what their activity level will be in a larger tank.
if its down to entertainment, I would skip the one big fish idea and do the community tank as already suggested.
you could do a fantastic, colourful and interesting rift lake cichlid tank in a 75