Lets see...
Default ringtone: David Bowie - Ashes to Ashes
SMS: The CTU desk phone ringtone from 24
Ringtone for anyone at the office: the Loony Tunes theme song
Ringtone for family members: Pink Floyd - Pigs on the Wing, part 1
Ringtone for business contacts: Led Zeppelin - Immigrant Song
I use other ringtones to identify specific individuals, such as;
The original James Bond theme song
The intermission track from Monty Python & the Holy Grail
Hard Fought from the Half-Life 2 soundtrack
Tears for Fears - Everybody wants to rule the world
Pink Floyd - Money
Jimi Hendrix - Voodoo Child (Slight Return)
I figure, I paid good money for
Ringo Pro, I'm going to use it, kak damnit.