in my standards...
best to me would be Chopin. Chopin has always been the "piano" composer to me. i could go on and on about why i picked him but you all probably know why... Rachmaninoff comes in second. other than that, I feel obligated to mention Kaikhosru Sorabji and Frederic Rzewski. Their music isn't as accessible as Chopin (or maybe even Prokofiev) but the technique, tone, and intellect required to play their music makes them stand out to me out of anyone. samuel barber's solo works, songs, and his concerto are all intesnse and strikingly beautiful. franz liszt, marc-andre hamelin, leopold godowsky, georges cziffra, and arcadi volodos have written some of the most virtuosic and imaginative transcriptions I have ever heard. Gyorgy Ligeti's piano etudes are gut wrenchingly complex and highly innovative. Leo Ornstein's earlier works are always fun to play when you really want to beat the scraggy out of someone. I always prefer a Nikolai Kapustin piece to be an encore being that he's very technically demanding and it appeals to everyone at a concert who was kind of dragged along even though they aren't into classical music. Arensky has written powerful works in the piano duo repertoire. Last but not least, i'm going to mention Ravel, because I love him