What piano/keyboard music would you recommend?

Hi, I’m making a playlist of the songs I have on my ipod that are piano/keyboard only. I’ve noticed that my selection consists mainly of rock covers, video game music covers, and some Beethoven. I’m looking to expand my collection to something a bit more sophisticated/diverse, so I am looking for some suggestions on good piano music to listen to. You can list either single works, artists, albums or even websites. Please note I am interested in pieces where the piano/keyboard(sounds like piano, not other synths) is the ONLY instrument being played. I like the minimalist sound of piano and how complex the music can be with only one instrument being played. I don’t really care if the music is classic or contemporary, original or covers. I like it all. It can be soothing and peaceful/beautiful or upbeat, or dark and brooding, or even chaotic. Magnum opus or short, 2 minute songs (short is good, but I like epic tracks as well). As long as it sounds good. So whatcha got? Btw as far as Beethoven I have his 9th symphony on piano, love it. Oh and of course moonlight sonata.