I have my male Betta in a tank with Mollies, Swordtails, Gouramis, and a Rainbow Shark. They all get along just fine. My LFS is currently on an education kick about Betta's. When you go in their store, you do not see any Betta's alone or in a small tank. Any tanks that a Betta can go in with other fish, that's where they are. I think it's great that someone is doing this so we can get those guys into larger tanks with room to swim. Mine love to swim around with everyone else. Good luck!
Steven