I've been a fan of classical music ever since I started playing the piano at around 5 years old..
Rachmaninov (I love the preludes), Chopin (nocturnes and mazurkas), Liszt (Liebestraum), Schumann (Fantasiestucke), Beethoven (Sonatas), etc. .
Recently I dated someone who loved classical music too, he introduced me to Alkan, which is some really really nice piano work in my opinion :D I have yet to learn anything of his, my current goal is some Rachmaninov and Liszt to avoid getting rusty.
It's relaxing, and also it's fun to show non-classical music fans that such composers "are actually pretty good".