Mine is The Sound of Silence. No, not the Simon and Garfunkel song, just complete silence: I don't have a cell phone.
Neither do I, which makes two of us. I have been told I'm smart for not having a cellphone, even though I'm in the minority, as I think up to 80% of the people in the U.S. not own a cellphone.
As for the song "Sound of Silence," I think it's a great song by a great musical duo and one of my all time favorite songs.