Friday the 13th Part 6: Jason Lives since that's when Jason went from a human psycho killer with a surprising amount of pain tolerance, to an undead killing machine with super strength. The Alice Cooper songs don't hurt either.
Hmm, good question... I've watched a TON of horror movies during my life so far... Best with the most sequels: Friday the 13th! *ohgawdilovejason* Most terrifying: The Grudge 1-2 (American) *nightmaresforaweekdammit* Best new one: Insidious 1-2 *demjumpscaresthough* Best old one: The Thing *mostawesomeeffectsever*
I agree but I must say that the American 2nd Grudge keeps up with the Japanese ones. Some scenes were really creepy - like the one on the beginning when one of the girls got closed in the closet and Kayoko was observing her from the attic... Brr... Even now when I think of this scene it gives me shivers... but in general, obviously the Japanese ones were much more terrifying. I can also recommend Shutter (like in the case of Ju-On there are American and Japanese versions but this time the American version is kinda poor when compared to the Asian one )