Cichlids are exactly what I was thinking. I started out thinking of Oscars... I've had them before, but they're tough to find tank mates for, and finding a pretty oscar isn't always easy. After oscars, my next choice would be a big pleco, and a big snail, with a bunch of brightly colored 4-6" cichlids. I want fish with some personality, who will greet me when I come into the room, and do intersting things like dig, and interact with each other.
If its personality and interesting things you are looking for then Cichlids are def your answer!
They each have a personality of there own, some are more aggressive than others and chase their tank mates around. They constantly dig and rearrnage the substrate, its quite fun to watch them move the substrate little rock by little rock from one place to another just so things are they way they want them.
Here's a link (If you havent already foind it or others) with a bunch of different types of African Cichlids. There's something there for everyone, lots of colors. Can't wait to hear your choices!
http://www.liveaquaria.com/product/scateg.cfm?pCatId=1825