Tough choice...I guess I would have to go with Paul (Grace a close second). For me, Paul was the driving force behind Jefferson Airplane and certainly the first few Jefferson Starship Albums. His spirituality, resolve and beliefs concerning the human race, government and our freedoms are what the early JA albums were all about. Paul insisted on pursuing these ideals in his music. Other members left the band because of this to pursue different directions in music. Jack, Jorma and Marty are perfect examples of this.
Have you seen the stars tonite?