Dolly Parton. In addition to what I'm sure would be a wealth of fascinating life experiences, I think she is one of the few who could be realistic about life, and yet still show me the way to stay optimistic about it all the same without the apathy.
Just off the top of my head, and listing a name I'm sure most here would recognize. And that would be even without realizing her own efforts to help make Buffy its own TV show. (Perhaps ironically, I'd ask the least about other celebrities. I think she'd be too classy to tell the truth about them anyway. 😛 )
I could do a whole list if I wanted, even if restricting it to women.