McCartney is the master of rock bass no doubt about it, many giants stand on his shoulders maybe not even realizing it. As much as I love Jim Lea, Entwhistle etc. Paul McCartney is always my first on my list of influences.
Man, how I can relate, Scott! It's incredible (and somewhat unsettling) how much I
still sound like him to this day. I never consciously emulated his style - I concentrated on people more in a hard rock vein such as Simper, Glover, Hughes (the DP Holy Trinity of Bassists), Martin Turner, Alan Lancaster, Gene Simmons and Jim Lea (though all of them cite Macca as an influence as well) - but otoh there has never been a time since my childhood when I did not enjoy listening to the Beatles.
I've always had a strong pop influence in my playing, my bass lines are largely melodic and give me half a chance to play the third rather than the root or the fifth, then I'll do it! McCartney'isms are littered all over my playing though I have never covered more than perhaps half a dozen Beatles songs in my life.