The apistos? They are often sold as trios, sometimes as a reverse trio (2m1f). Or you can try 3 males - they are the colorful ones. Depends on what it is you wish to see of the fish. A trio is a breeding group, so if you want to experience that then that's what you should go with, possibly even adding another female or two for the haram experience. If you want pretty fish that spar from time to time (also interesting, and totally natural behavior), then go with 3 males.
Stocking has a large trial and error component to it. These forums are nice and all, but the pitfall is that many people don't find things out for themselves, so their understanding of the hobby becomes very myopic. People can get wrapped up in theories, but there's always a gap between theory and practice. While it is our goal to prevent people from having problems, dealing with problems is how we learn. So don't be afraid of trying things, as long as you've done some homework