One of the advantages of enjoying classical music is that I've always found it easy to find inexpensive or free classical music collections at the store and online. Granted, if you are more than a casual classical music consumer (wow - that worked out alliteratively) you'll want to be aware of who is performing what, which is why Classic Cat is a good place to look into.
You can search according to composer, instrument, performer, or genre, or just jump straight to the 150 most popular downloads. (The music available there is not hosted at Classic Cat; the links lead to the individual performers' websites.) Since all the music is free, you can afford to listen to several performances before choosing your favorite. Or just keep them all and make a super cool CD of all the variations you can find of Pachelbel's Canon.
What? No, I have never heard the version with the whales. Really.