I don't really care about phones, mine is used for nothing more then the occasional phone call, sending ridiculous text messages, and setting up the occasional pot buy. As such, in the 7+ years of having a cellular telephone, I've only used two ringtones aside from the one that comes standard on the phone.
Beastie Boys - You Have to Fight For Your Right
Wu-Tang Clan - C.R.E.A.M
C.R.E.A.M received the best reaction from people, probably because it is a lot more melodic.
I can see you totally disregarding every bit of opinion I just put forward. But the next time you find yourself walking through a "rough" neighborhood and your phone goes off, you'll be wanting to thank me for the huge amount of respect you'll receive from the local populace. So in advance, your welcome.