My two cents:
I would have included Cafe Blue as well except there is one cut on it that I always skip over.
Many people suggested Joni Mitchell's Blue and that is a good choice although I personally prefer Hejira.
Kind Of Blue deservedly made many lists including my own although I get the feeling the OP was thinking about rock and pop.
You can certainly tell a lot about a poster by the music he/she listens to.