Despite the fact that none of the stories are actually creepy. The few I can give some credit to for being well written are: The Russian Sleep Experiment. Robert the Doll. Ben Drowned.
Not a creepy pasta but definitely this series: http://www.reddit.com/r/nosleep/comments/1nyt4a/the_spire_in_the_woods/ It's really long (10 parts) but it pays off.