(in no particular order)
PSYCHO (Hitchcock's best, after Rear Window)
PEEPING TOM (Disturbing, and way ahead of it's day)
DR TERROR'S HOUSE OF HORRORS (Best horror omnibus movie)
THE MASQUE OF THE RED DEATH (Brilliant cinematography)
REPULSION (Distubingly original, and still is today)
THE PLAGUE OF THE ZOMBIES (One of Hammer's best Directed)
THE DEVIL RIDES OUT (Possibly Hammer's most accomplished)
QUATERMASS AND THE PIT (Hammer's most atmospheric)
ROSEMARY'S BABY (Polanski's best film and one that will age well)
What about your tenth?!!!!!!!
Like all lists, you never like to leave any out. So I am going to list a few I would also like to include, as you can never put a good movie down. THEY ARE:
THE INNOCENTS, HOUSE OF USHER, WHATEVER HAPPENED TO BABY JANE, THE REPTILE, DEVIL DOLL, THE GORGON, THE HAUNTING, and finally possibly the number 10 choice: THE WITCHFINDER GENERAL!