One thing to remember before you digest this list -- it does NOT include any city I've called home. So, no New York (which wouldn't have made it anyway), Los Angeles or any other former or current home.
With that in mind:
10. Philadelphia: You'll love the Liberty Bell.
9. Budapest: If you ever go, eat at the Citadela Restaurant.
8. Dallas: The Texas State Book Depository is one of the few places that has left me speechless.
7. Minneapolis/St. Paul: If only there was no such thing as winter.
6. Annapolis: Deserves to stand apart from Washington or Baltimore.
5. Boston: With Harvard and MIT, perhaps the smartest city in the U.S.
4. San Antonio: Forget the Alamo, there's plenty more to enjoy.
3. Toronto: Cultures from all over the world. Great food right along with them.
2. Paris: I wish I'd have had more time there.
1. Washington, D.C.: Oozes with history, culture, power and fun.
Honorable mention: (in alphabetical order) Baltimore, Denver, Evanston (IL), Newark (DE), Las Vegas, Little Rock, Mexico City, Oklahoma City, San Diego, Santa Barbara