If your chosen themes accommodate one another, you can create a unifying theme. Consider this: your spouse wants an Asian theme, your teenage daughter wants a gothic theme and you want a tropical theme. In such varied combination you may plan to do an around-the-world theme inside your living room; this is like a miniature version of Disney's Epcot. You can incorporate Asian tropic dragons, samurai and plants swords that would incorporate all three themes. The point is, regardless of the themes, there is common ground available.