Definitely love Debussy, especially 'Estampes', I was mesmerized when I first heard that suite. And Beethoven is a close second for me... so much passion! I never realised how amazing Bach was til I played it... for me the most challenging to play. John Field is definitely overlooked... creator of the nocturne.
I'm really loving some of Shostakovich's prelude and fugues atm... quite dark musically though.
You have great taste. I'm relaxing with the 'Estampes' now, and I want to learn it. Playing Bach well is so hard, but it's stunningly beautiful when you do. I like the way Glenn Gould emphasized the hypnotic quality of Bach's music instead of focusing on speed.
I agree that Shostakovich is dark, but enjoyable. I have to be in the right mood for it.