Some of my favorite classical music includes works composed by Ludwig Van Beethoven and Frederic Chopin. The Beethoven album that I listen to most are his Piano Sonatas; there are enough of these to last for an entire day of listening, so I like to turn these on in the morning when I start working and listen to them all day. The Chopin albums I like are Nocturnes, Waltzes Nos. 1-14, and Piano Sonatas.
Listening to classical music is very relaxing and makes you smarter.
I listen to these on Rhapsody because this allows me to listen to almost anything I want, anywhere I have access to the internet. But it's all available on CD, too.