Another show that I'm getting into is Chuck. Which again has the strong female characters, the witty banter, and Adam Baldwin too. It also plays with the gender roles. Chuck's the main character, but everyone around him is "better" than him. His sister is a doctor; Chuck got expelled from Stanford. Sarah and Casey are better at fighting and spying than him -- often Chuck freaks out when there's fighting and shooting. But since he's the everyperson character, that makes sense. Most of us would react that way.
While the main characters are white, the show is set in LA so there are Asian American characters. For example, Anna Wu is Taiwanese American and an episode used that as a major plot point. That's one thing Chuck has over Firefly. The Firefly 'verse is supposed to be a blend of Chinese and American, but there are no Asian actors? Come on!
Also, all the characters are believable characters on their own, and their relationships with each other, separate from Chuck, are believable. One of my favorite websites is Television Without Pity (TWOP, see link on the right). On the Chuck forum, there's a thread called "Relationships: Romantic and Otherwise" where users post their thoughts about that topic.
Another one is called "HoYay: Rhymes with Chuck" that has lots of good, and sometimes extensive, posts about how the show plays with gender roles.