Well, Paul IS the greatest bass player in rock 'n roll.
Some will argue Motown bass player James Jamerson has had as much or more influence as Paul--
but after Paul and Jamerson, there isn't anyone really even close. Basically, if you looked at who has played bass on the most Top 10 hits, Jamerson and Paul are all alone at the top. If you look beyond the charts, Paul has certainly played on many more influential recordings.
Next would probably be Entwhistle.
http://en.wikipedia.org/wiki/James_JamersonJames Lee Jamerson (January 29, 1936 – August 2, 1983) was an American bass player. He was the uncredited bassist on most of Motown Records' hits in the 1960s and early 1970s (Motown did not list session musician credits on their releases until 1971), and he has become regarded as one of the most influential bass players in modern music history. He was inducted into the Rock and Roll Hall of Fame in 2000.
Jamerson's discography at Motown reads as a catalog of soul hits of the 1960s and 1970s. His work includes Motown hits such as, among hundreds of others, "Shotgun" by Jr. Walker & the All Stars, "For Once in My Life", "I Was Made To Love Her" by Stevie Wonder, "Going to a Go-Go" by The Miracles, "My Girl" by The Temptations, "Dancing in the Street" by Martha and the Vandellas, "I Heard It Through the Grapevine" by Gladys Knight and the Pips, and later by Marvin Gaye, and most of the album What's Going On by Marvin Gaye, "Reach Out I'll Be There" and "Bernadette" by the Four Tops, and "You Can't Hurry Love" by The Supremes. According to fellow Funk Brothers in the 2002 documentary Standing in the Shadows of Motown, Gaye was desperate to have Jamerson play on "What's Going On", and went to several bars to find the bassist. When he did, he brought Jamerson to the studio, who then played the classic line while lying flat on his back. He is reported to have played on some 95% of Motown recordings between 1962 and 1968. He eventually performed on nearly 30 No. 1 pop hits—surpassing the record commonly attributed to The Beatles. On the R&B charts, nearly 70 of his performances went to the top.