Probably a tie. There's the bass I learned on: a '77 Music Man Stingray body with a fretless 1980 Sabre neck. I don't really love it, but it's very sentimental. Then there's my '76 Musicmaster Bass, which my dad bought brand new, and I inherited. I still gig with it more than any other single bass I own, and it's even more sentimental to me than the Music Man.