Psycho, His Girl Friday, Casablanca, Dr. Strangelove, All About Eve, Tokyo Story, A Bout de Souffle, Touch of Evil... the list goes on. All treasured film memories to me; all in glorious black and white. (In fact, I'm planning on watching His Girl Friday again tonight, I like it that much!)
Black and white cinematography, just like colour cinematography, can be done well or poorly. Sometimes, its modern stylistic usage can be good - see Schindler's List - or bad - see Tetro or The White Ribbon for exercises in pretension. With regards to people who do avoid black and white films, I wish they wouldn't; what annoys me more, however, is just not liking them sight unseen. There are many reasons why modern day audiences may not like them - a preponderance of story and character over explosions and bikini shots - but to simply dismiss them because of their lack of colour is a really short-sighted way to go... like foreign films (but that's a whoooooole other battle for me to get into -_-).