Any single person being the "best" musician is absolutly impossible. In music a piano virtuoso is equal to the drunken ass playing off key harmonica at open mic night at the local bar. It's all in how the feelings and intentions of the artist resonate with the feelings and intentions of the listener. So instead of writting who's best, I'm going to write some musicians that are important to me.

JS Bach- Organ virtuoso, standardized many aspects of modern musical notation, helped pioneer tempered tuning. Without Bach music would be a very different place.

Beethoven- I could put any number of composers in this spot from Midieval times to now, but I love the drama of Beethoven's music.

I was led to classical music by my interests in some of the great music I was around when I was a younger kid (in my parents record collections, not anything from my time). Here are a few of those.

Emerson, Lake, and Palmer- Three amazing instrumentalists playing amazing music. If you have never heard them you should check some of they music out. You'd be amazed by how much ass a drum, bass, and keyboard trio can kick.

Jimmy Page- I always thought of Jimi Page as a true master of making a deep rock record. Led Zeppelin always seemed in touch with the deeper parts of music.

There are so many more and I could go on for days.