All the big towns or college towns of Texas -- Dallas, Austin, and the various suburbias. When I do see people in blazers, it's either in a #menswear context, more of a club thing, part of a self-conscious shopping outing, or (more comfortably) plays, concerts or museums. Never just hanging out. This could just be my peer group, though.
I know when I visit my uncle's family in Portland, though, it's just as DLester says -- dudes ripping it up old school, no one commenting!