It'd be tough to argue with your choices, WNO. If those families don't all make my own Top 5, they're all up in the Top 20 or so.
Here's a pass off the top of my head, in no particular order:
Kennedys
Rockefellers
Roosevelts
Bushs
Hearsts (just to be different)
Some good names there, Akillies, but they were gone or had accomplished almost everything before 1900.