I am a nerd who read the original source material and preferred it to pretty much everything else, and in the original Holmes stories he had a non-curved pipe and was primarily hatless. The curved pipe was actually an anachronism at the time it was introduced (in that one Sherlock Holmes show that made him popular again), but the actor-dude couldn't actually speak and hold a straight pipe in his mouth at the same time, so that sorta just fell into pop-culture and stuck in the sludge of misinformation that coats all of everything.
I thought the hat in the show Sherlock was acceptable as a parody of the common misconception as to Holmes's appearance.