I wear my black 30th anniversary D&D t-shirt from last year's GenCon (the one with the beholder drinking a beer on the back) pretty much anywhere that I'd wear any other t-shirt. It's a classy looking t-shirt, so yeah, I'm proud to wear it.
However, I also have a "I just rolled a 20, so you bitches can suck it" t-shirt. While this t-shirt gives me no end of personal entertainment and enjoyment, the profanity on it limits how often I can wear it in public.