Classical Top Five

J.S. Bach is number 1.

2 and 3 are Beethoven and Schubert or Schubert and Beethoven.  Listen to Schubert's Lieder and piano sonatas then explain to me how he is not deserving of this ranking.

4 and 5 are Brahms and Haydn or Haydn and Brahms.

You can fill out a top10 with Mozart, Tchaikovsky, Mendelssohn, Schutz, and Mahler in whatever order suits you.  

I'd develop a separate list of post romantics.   Call me crazy, but Benjamin Britten might be at the top of that list for me.  Exquisitely crafted music.

@larryi I hear that comment about J.S. Bach being "stuck in the Baroque."  In a sense it is true, in that he persisted writing High Baroque after everyone else had moved on.  

The reality is that while remaining true to the baroque style for 2 decades after everyone else began to move on, that late High Baroque music went to the pinnacle of western music.  In that sense, he most certainly was not stuck anywhere.  The Matthaus passion is the greatest piece of music ever written by a human being.  If that is stuck, then give me more stuck. 

As for influence, while it is true that J.S. Bach's music was largely lost to the public until Mendelssohn reintroduced it to the public, it is not true that his work was unknown to the cognoscenti.   His influence on Beethoven is well documented as is his influence on Mendelssohn.   I'd argue that apart from Beethoven's early exposure to J.S., Beethoven would not have become the Beethoven he became in his maturity.   Beethoven didn't get the late quartets and piano sonatas from Haydn or Mozart.

For many of us, the music of J.S. Bach is the standard against which all music is judged.  C.P.E. Bach?  Not so much.