Peter, I think a better poll question would have been: "What is the aperture of the scope you use most often?" and then taking the average of all asnwers.
Mine is an 8". But the average amongst those who are taking the hobby at least semi-seriously is probably 10". Although like Scott says the refractor faithfuls might bring that figure down.
... and if you include all the wobbly department store 60mm refractors around, then the average is probably around 60.02 mm.