How about Carpenter's The Thing, The 70s' Invasion of the body snatchers, The Blob and Nosferatu, the vampyre.
All films i rate, there's also the remakes of Dawn of the dead and Night of the living dead, i prefer the originals but they are both pretty good.
I agree most are shite but there are always exceptions.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.