My favorite one is Julia Child, who was a close friend of my grandmother's (and yes, Grandma is portrayed in Julie & Julia!)... I had dinner at her house once, the day after Thanksgiving so - believe it or not - we had leftovers!
I live in DC where there are celebs (mostly politicians and newspeople) everywhere, esp. if you look for them (e.g., Eliot Spitzer, Alan Greenspan, Chris Matthews, Colin Powell, Ralph Nader, Bill Clinton, Newt Gingrich... yawn). But I think it's particularly odd that I have seen Icelandic singer Bjork in public not once but twice: once in the Dallas airport, and once in DC, in front of the Mayflower Hotel (where Eliot Spitzer was humiliated!).