McCartney.
Another vote for McCartney.
Of course in the news lately was Paul Walker.
A lot of Paul musicians…
Paul McCartney
Paul Revere and the Raiders
Les Paul
Paul LaAbdul
Paul Anka
Paul with Peter & Mary
Paul Simon
Paul Rodgers
Paul Hewson (Bono)
Paul Schaffer
Another McCartney.
I came up with others, but McCartney was definitely my first thought upon seeing the thread title.
The alien like in post 34.
The titular alien from the movie Paul. I don’t know why; it wasn’t a very good movie.
Paul the Apostle
Paul McCartney
Paul Molitor
St. Paul, the city in Minnesota
My dad.
Is he now, or was he ever, a member of the Beatles?
McCartney
Yup. McCartney.
I see what you did there! 
the apostle
McCartney, followed quickly by Pope Paul.
Paul the Apostle and I’m not even a Christian. Second was McCartney.
The McCartney.
Then the saint.
Yea, I’m kinda surprised Paul the Apostle isn’t dominating. He was mine, despite the fact that I’m not religious, and wasn’t raised in a particularly religious household.
Plus he’s the Paul most frequently referred to by first name alone, so he’s the one that leaps to mind when I hear just the name without any qualifier or lastname.
Now if you asked who the first person that popped into my mind when you say “Ringo”…
Paul “Bear” Bryant, cuz ROLL TIDE!
I actually thought of Paul Rudd instantly. To be fair, i was just watching I love you, man the other day, followed by repeated viewing of the outakes (Klavenisms) video on you tube.