Surfing is Scary!
rhetroCRUSH has a list of their 100 SCARIEST MOVIE SCENES! The Crate Monster from Creepshow and Michael Myers is high on my list as well!
About.com has a Top 10 Actually Scary Sci-Fi/Fantasy Movies for Halloween that lists the wonderfully scary Aliens at #1, but then cops out with Jurassic Park at #3, Whatever!
Cryptomundo has a list of The Top 50 Cryptids From Around The World