My tree has several different themes too - I am a registered nurse. Hallmark comes out with a themed nurse ornament every year and my parents have been getting me that ornament since I've become a nurse, so I have quite a few of those.
DH is a firefighter, so he has quite a few of firetrucks and different things to do with firefighting.
Over the years, I've also collected snowglobes and Precious Moments, so for the majority of the other ornaments, that is what is one our tree. We also have other types of ornaments, but those are the "themes".
The best of all gifts around any Christmas tree: the presence of a happy family all wrapped up in each other.
- Burton Hillis