I use “Holiday in Cambodia” from the DK. Certainly never heard that one anywhere else.
Mix it quiet, and almost anything can work.
I like to use the Super Mario Bros Theme. It’s pretty easily heard above the general din of life and sometimes even puts me into a good mood.
Plus, every so often, somebody will recognize it (whether they can place it or not) and it makes a good conversation piece.
I’m assuming you make your own by editing mp3 tracks, yes?
Currently on my phone (most being used as signature tones for the important people who call):
Outkast - Bombs Over Baghdad (just the chorus)
Harold Faltermeyer -* Axel F* (the Beverly Hills Cop theme)
AC/DC - Big Balls (just the chorus)
Rob D(ugans) - Clubbed to Death (from the Matrix soundtrack)
The Fraggle Rock theme- always good for a giggle
The Instinct - the main theme from the game Killer Instinct
7 Seconds of Love - Ninja: http://www.7secondsoflove.com/ninja/
Nas - One Mic (Massive Attack instrumental-only remix)
The Rocky theme - forget what it’s called… the trumpet one, not Eye of the Tiger
Men Without Hats - The Safety Dance
The Ataris - The Radio Still Sucks… only 27 seconds long so required no editing at all
Overseer - Supermoves (approx. 30 seconds starting at 2:55)
NIN - Closer (a really, really quiet mix in case I forget to put the phone on silent at work or something)
Need to make some new ones, I think.