Even though I prefer the our US version of "The Office" to the original, I still use the instrumental version of "Handbags and Gladrags" as my ringtone.
The first couple of notes are distinctive enough for me to notice without being too loud or intrusive to whatever surrounding I'm in.
Plus, it's a test of coolness. I'm waiting for that right person to say, "hey, I know that!"
(People calling me, however, do get the US theme as the ringback tune as the call is being connected.)