This movie has always stayed with me. Yes it's rather dated, and the effects compared to today's are lame, but still it conveys a certain level of genuine creepiness that, well, current horrors rarely deliver. I suppose this comes from the music, Brian de Palma's direction, and the focus on Carrie's relationship with her Christian fundamentalist mother, played wonderfully by Piper Laurie. Ultimately the tension and abuse Carrie has had to endure both at school from bullies, and at home at the hands of her crazed mother, culminate in perhaps one of the most famous scenes in movie history. Its build-up is just as amazing, as it ratchets up the tension immensely to the final "bloody" act.
So, put away your brash, overboard modern day Hollywood horrors ladened with gore and nothing else. If you want a real horror movie that stays with you, that affects you in ways you might not understand, get this movie.