I've kept mine from the days of AOL dial up where I tried a number of combinations and my "handle" had the lowest number atachment available - at least my first name isn't John. 

The coolest one (depending on your 1960's Brit TV knowledge) I've seen was one of my university classmates - "I_am_not_a_number".

As to a Renderosity version of this servey - either they or someone else will have to do it since I've had my turn at the front line.