If 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 choose to do an around-the-world theme inside your living room; this is like a miniature version of Disney's Epcot. You could potentially incorporate Asian tropic plants, dragons and samurai swords that would incorporate all three themes. The point is, regardless of the themes, there is common ground can be found.