Here's a great article (actually a transcript of a speech) about cell phone ringtones from the perspective of someone in the audio business (Peter Drescher, a sound designer for Danger): Could Ringtones BE More Annoying?!

The ringtone thing is one of those things that I don't really understand. I find personalized rings stupid and completely annoying, too, yet I've purchased several of them myself. I don't have enough nerve to actually use them, though -- my cell phone is set to the "Continental" ring which is, I believe, the sound that telephones make in Europe. Maybe. It's different, but not too different.

My cell phone also contains ringtones of "Lucy & Linus," "The Pink Panther," "The Addams Family Theme," "Jingle Bells," and several others that I'm too embarrassed to actually play in public. No, that's not true -- it's not really embarrassment. It's just that other people's rings are so annoying that I can't subject anyone else to my own. They're still cool, though.

Link from Ceej.