I think I agree with others that the perception of someone being or having been famous depend on the age of the person remembering and the kind of things they are into (movies, TV series, songs, etc).
When I read the your AIBU headline about Minnie Driver I knew exactly who she was. Funnily enough, I don't think I know or remember much of her face that I would be able to recognise her, or that I remember her from any of her work as an actress (for example, I watched Good Will Hunt when it first came out and I didn't know Minnie Driver was in it).
The reason I know her name is because she was Tom Cruise's first wife. They were married briefly, and if my memory is correct, they were married when Tom met Nicole Kidman on the set of Days of Thunder. I remember it was a bitter divorce, Tom didn't speak well of her, and that Minnie was older than him. I believe at the time Minnie and Tom got married, Minnie Driver was actually the famous half of that couple.
I don't know how but all that entanglement caught my attention at that time, maybe I read an interview with some of them on a magazine and I never forgot about it.
Whereas I didn't know who Neve Campbell or Mena Suvaris were until you explained where they had been. I remember watching Party of Five, so that rather than Scream is what makes me place Neve Campbell. And I remember the fuss about American Beauty with all the Oscars it won, and the American pie movies, so I know now who Mena Suvaris was.
But if I had to say who had been the most famous in my mind out of those three, I would have to say Minnie Driver, because that's the one I remember being famous at that time.