Marty, Johann’s day job was as a church organist, and it was his main axe ;-). He wrote a LOT of music for organ---it gave him something to play! Wasn’t the fortepiano (the predecessor of the piano) already around in J.S.’s time? I absolutely (no pun intended!) love his harpsichord works.
I realize my opinion of Hendrix’s guitar playing is an extreme minority one. I don’t think I’m "right", and don’t expect everyone, or even anyone, to agree with me. I mentioned him only in my attempt to satisfy Slaws suggestion that I define "great" in regards to musicians. In order to do so, I felt I needed to put it in the larger context of music itself. Which brought up the subject of songs. I really, really love songs, and have a very well defined and specific idea of what constitutes a real, real good one. That idea appears to differ from that of some others here, which is, of course, fine. It’s all good!
I have played with a lot of guitarists (and some bassists) who hold Jimi’s guitar playing in very high regard, and I fully realize he revolutionized the playing of the instrument. I view Jimi’s playing as I do that of Jazz musicians; It’s more about the instrument itself, and exploring it’s possibilities, than of playing a song as a song. The song itself is the framework, or skeleton, upon which the music is built. What I hunger for from music is not generally provided by that type of music. Improvisation and soloing provide one kind of musical high, I’m looking for a different kind.
In Jimi’s music, there is no harmony singing, and very little melody of any interest or substance. The chords and their progressions are bone stock, heard a million times before. Jazz music is often musicians improvising or soloing on the same chord for what seems like an eternity. Not all Jazz, no. But the chords used in Jazz are commonly "self-consciously" sophisticated, and kind of corny. I refer you to the dreadful, unintentionally hilarious Steely Dan. Such music is of absolutely no interest to me. To each his own!