The U.S. Census Bureau has just released a listing of the most common last names (surnames) in the U.S. based on Census 2000 data. The ten most popular last names are:

1. Smith
2. Johnson
3. Williams
4. Brown
5. Jones
6. Miller
7. Davis
8. Garcia
9. Rodriguez
10. Wilson

On the Bureau's website, you can download Excel files of the top 1000 names and a file of all 151,671 last names that occur 100 times or more in the data.