There is a really cool place in Denver called Wizard’s Chest. I think they make good money off costumes, but also Warhammer 4k (and to a related lesser extent DnD). Nice people, too.
It's Warhammer 40k.
But beware, this game is designed to suck your wallet dry! ;)
Game stores tend to make money off Magic The Gathering, from my understanding. But yeah, The Wizard's Chest also has a decent miniature gaming community as well. And their board game selection is pretty good.