On the first day of school my 9 year old had to complete a sheet detailing facts about himself. Under the category, Favorite Musical Group, he listed the Alban Berg String Quartet. I'm worried he's going to get beaten up.
Don't worry, when my son was that age his favorite was Carl Orff's Carmina Burana. He still listens to Carl Orff, but added "Bright Eyes," "Radiohead" and all the other stuff 19 year old's pick up from the radio and friends I-Pods.
Until then, you can always enroll him in a self defense class :^).
Congratulations to the father. Thanks to you your son as a broad vision of music, with no prejudice about XX century music. As for a recording I recomend for the Quartet and the Lyric Suite a reading under the Alban Berg String Quartett, on the EMI label.