Met three that I can think of off-hand.
Terrence Hardiman (Demon Headmaster, more recently in Dr Who). Was in my shop asking about lightbulbs. Took me by surprise initially, but was a nice bloke.
Burn Gorman (Torchwood, latest Batman film). A total up-himself douche. Used to live in my town, but not a decent bloke. Quite happy he moved away. I cringe whenever I see him in something.
Gloria Hunningford (TV Presenter). She still lives nearby to my town and I see her quite often. Actually knows my name as I've helped her a few times in my shop. She seems quite nice.
That's 2/3 who aren't idiots. Not massively high-profile, but high profile enough.