north west england, I wear square cuts ( or sunga style briefs if i'm feeling brave) 
couple of other guys my age wear jammers, most of them wear shorts. 
few guys in there 30s/40s wear boxer cuts or speedos
and a lot of older guys who wear speedos
no ones ever commented on my choice of swimwear, the only ones who i ever think might do are the younger guys in baggy shorts, but i swim better than them so  
 
  
 
(really though, i think a couple of them might wish they had the confidence to wear square cuts or speedos)