Lots of contenders for this prize.
It's No Secret, but I think this song was live played much better than on "JA Takes Off", certainly after Grace joined the band. She Has Funny Cars, Somebody to Love or White Rabbit. These three songs started my lifelong affair with JA. The House at Pooneil Corners, We Can Be Together, Volunteers, Good Shepherd, Eskimo Blue Day,Third Week in the Chelsea, all these songs might have made it to #1.
But two songs prevent that: Rejoyce and The Ballad of You & Me & Pooneil.
Rejoyce is one of the best songs Grace Slick has ever written, but it is surely the best produced of all her songs. That glorious vocal, that stunning jazzy arrangement (thanks to Spencer). But in the end I go for Ballad, because it is not only on record a fantastic experimental song ("atonal rock") with those characteristic vocals, Jack's bass and Jorma's unleashed guitarplaying, that showed for the first time what an excellent guitarplayer he would become, but also live it proved te be one of those songs that challenged the band to give their best. Listen to "Ballad" live at the Monterey Pop Festival or at Woodstock.