I agree that Kempff isn't a good pick for Chopin, esp.

Chopin's short pieces. I put his clip there for the reason of variety. But his Beethoven sonatas are gorgeous, the Pathetique, wow!

That's interesting, Haskil holds my attention with her Mozart whenever I listen to it, and her contryman Lipatti's renditions of Mozart's sonatas are quite good as well.

Have you tried Mozart's violin sonatas by Haskil and Arthur Graumiaux? brilliant.

I'm not familiar with Hess' works, will give it a try one of these days.