A large tropical community tank! That's what I'm doing with my 75gal. If I could make the perfect 75 with my tank, the below is what I would do:
24X Neon Tetra - Not very original. but hey, they aren't evil because of it. Neons are a very beautiful small fish that can get along with just about anything that won't eat them.
9X Serpae Tetra - Very beautiful fish that do better in a school like this. I like em because the remind me of my black skirts, which I've given up on keeping.
9X Praecox Rainbowfish - I've always wanted these, but never had the space and money to get them. But now I DO have the tank in the OP.
A pair of rams as the centerpiece fish - Awesome fish, they won't breed even as a pair in a community tank (AFAIK).
9X Corys (any will do) - Active and fun little fish, no tank is complete without them IMHO.
9X Hatchets - I've always wanted these too, but... well, I have no tight fitting hood to keep them. They are very nice looking fish.
2X Briggs/Mystery Snails - They are big, cool, and fun to watch.