I'm blown away by Mozart's piano sonatas. As much as I don't enjoy most of his concertos, I love the chamber music. I listen to Glenn Gould's recordings a lot. He doesn't mumble as much here as he does when playing Bach and well, he's great. I also have Friedrich Gulda's recordings in iTunes.
It took me years to get into Mozart and now I feel almost enlightened. His music sounds like it's SUPPOSED to be this way and like there's no other way it could possibly sound. It's truly perfect in a sense.
EDIT: I know this sounds retarded coming from a person who listens to shitload of all kinds of music and after all these years says "omg Mozart" but that's the story folks.