Forbes publishes its 400 richest for 2003: http://www.forbes.com/2003/09/17/rich400land.html

Here are the first 25:

Rank Name Worth ($) Age Residence Source
1 Gates, William Henry III 46.0 billion 47    Seattle , WA    Microsoft
2 Buffett, Warren Edward 36.0 billion 73    Omaha , NE    Berkshire Hathaway
3 Allen, Paul Gardner 22.0 billion 50    Mercer Island , WA    Microsoft, investments
4 Walton, Alice L 20.5 billion 54    Fort Worth , TX    Wal-Mart
4 Walton, Helen R 20.5 billion 84    Bentonville , AR    Wal-Mart
4 Walton, Jim C 20.5 billion 55    Bentonville , AR    Wal-Mart
4 Walton, John T 20.5 billion 57    Bentonville , AR    Wal-Mart
4 Walton, S Robson 20.5 billion 59    Bentonville , AR    Wal-Mart
9 Ellison, Lawrence Joseph 18.0 billion 59    Redwood Shores , CA    Oracle
10 Dell, Michael 13.0 billion 38    Round Rock , TX    Dell
11 Ballmer, Steven Anthony 12.2 billion 47    Redmond , WA    Microsoft
12 Anthony, Barbara Cox 11.0 billion 80    Honolulu , HI    Cox Communications
12 Chambers, Anne Cox 11.0 billion 83    Atlanta , GA    Cox Communications
14 Kluge, John Werner 10.5 billion 89    Palm Beach , FL    Metromedia
15 Mars, Forrest Edward Jr 10.4 billion 72    McLean , VA    Mars, Inc.
15 Mars, Jacqueline 10.4 billion 64    Bedminster , NJ    Mars, Inc.
15 Mars, John Franklyn 10.4 billion 67    Arlington , VA    Mars, Inc.
18 Johnson, Abigail 9.8 billion 41    Boston , MA    mutual funds
19 Redstone, Sumner M 9.7 billion 80    Beverly Hills , CA    Viacom
20 Ergen, Charles 8.9 billion 50    Denver , CO    EchoStar
21 Newhouse, Donald Edward 7.7 billion 73    Somerset County , NJ    publishing
21 Newhouse, Samuel Irving Jr 7.7 billion 75    New York , NY    publishing
23 Pritzker, Robert Alan 7.6 billion 77    Chicago , IL    hotels, investments
23 Pritzker, Thomas J 7.6 billion 54    Chicago , IL    hotels, investments
25 Johnson, Samuel Curtis 7.4 billion 75    Racine , WI    S.C. Johnson & Son