Simple. What ringtone do you find most entertaining/appealing. Also, what's the single most annoying one. My current ringtone is the intro to:
I don't know what it is about that song, but I've always found it very appealing. Very simple. I used to use part of Supernaut by NIN but some folks here in TN apparently thought that meant I worshipped satan, so I went to the generic ringing noise but that's not much of a conversation starter. This new one seems to work on all levels: it's not overly well known, it's not going to offend anyone, and pink floyd fans/girls who think it makes me sensitive always comment on it.
Most annoying had to be during the "I'm Rick James" phase everyone I know seemed to go through.