Favorite movie monsters.

[JediScum]

I've only seen Pinhead in this thread once but i have to go with Cenobites as a concept in general ("explorers of the furthest reaches of experience... angel to some, demon to others").
The Mugwumps in "Naked Lunch".
Swamp Thing.
Mr. Hyde in "League of Extraordinary Gentlemen" mainly because it was an actual suit and makeup, not CGI.
And a lot of credit should go to the microwave in the first Gremlins movie that nuked a mogwai. It seemed to scare the shit out of a lot of concerned mommies, eventually creating the PG-13 rating.