Beethoven, hands down, for the following reasons:
- Nine of the greatest symphonies ever written, so much so that composers for the next 50+ years struggled to stretch beyond his shadow. These symphonies displayed not just the compositional brilliance possessed by many other composers, but also the importance of the revision process, by which he honed his art to the point of completely overhauling the symphony and defying "correct forms" which are taught in today's college composition classes. While many composers were embarrassed to ever let others see anything other than their best work, whether intentionally or not he left his work process open to his successors. For this, he also deserves the title of best composition teacher of all time.
- His string quartets underscore the previous title. Unlike his symphonies, they are used extensively as instructional material in studying compositional form & analysis.
- The greatest pianist of his time until Liszt, he wrote revolutionary works for piano which even Chopin struggled to surpass.
- In contrast to utter nonsense that someone here (no direct quotes) wrote, despite not having the same genius for melodic compositional as Mozart who preceded him, some of the greatest melodies ever written are present in his symphonies (#5 mvt 2, #6 mvt 1 & 5, #7 & #8 mvts 1), sonatas (Pathetique mvt 2, Tempest mvt 2 and others), string works (various), etc. It is certainly true that Beethoven incorporated the arpeggio in many of his melodies, but they are in no way reducible to that. However it is possible to understand how someone could arrive at this conclusion, seeing how Beethoven was possibly the best orchestrator of all time, and used this skill heavily to supplement his melodies by not leaving the melody with any one voice for long.
- At least three choral works (Mass in C, Missa Solemnis, 9th Symphony) that each captured the human spirit in ways never before seen.
- The most inspirational composer of all time, having overcome a harsh childhood, social awkwardness, financial trouble, and deafness itself.