In the event your chosen themes accommodate one another, you can create a unifying theme. Think of 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 decide to do an around-the-world theme in your living room; this is like a miniature version of Disney's Epcot. You could potentially incorporate Asian tropic dragons, samurai and plants swords that would incorporate all three themes. The idea is, regardless of the themes, there exists common ground to be found.