One family name I"ve been debating is MacNamara. The story line will be my father was the famous MacNamar of "MacNamara's Band". That's an old, Irish, (US Irish not traditional Irish), song that my little grandson loves to dance to, and since I have Irish step dancers in the family it's pretty easy to come up with something sort of Irish or Gaelic. Could really work up a good story line with that one though.
My great granddad came here to the US from Ireland when he was a young man. Since he came here during a time when the Irish wasn't always welcome he changed his name to Mack. He thought it sounded more American. I wish he would have left it the way it was.
If I'm creating a theme family I'll Google name sites that apply, as in traditional gypsy names or what ever applies. I tend to go for odd names though. I like the funny, sort of satirical names that the Sims creators come up with.
Some of the names I've used:
Ima Hogg (bet you can guess her traits)
Sue Flay (a chef)
Manni Cotti (my Italian looking chef)
May Dye
Will Dye (her husband)
Stormy Day
Max Power (an adventurous explorer)
Gussie Upps
Summer Holiday
Dawn O'Day (I actually knew a woman with that name)