This is pretty random, yes, but who cares.
I'm sure pretty much every cellphone on the market nowadays supports .mp3 or at least .mid file playback, thus letting you apply a custom sound to almost any process in the phone.
So go on and post the music/tone/sounds you're using on yours, discuss them, etc..
As for me, I'm using the last minute of Thomas by A Perfect Circle as my ringtone and the initial chords of Bad to the Bone by ZZ Top as an SMS tone.