The Hammer film I always come back to (and enjoy more than any other, which is quite something as nearly all of them are enjoyable for one reason or another) is
Captain Kronos - Vampire Hunter. Horst Janson makes quite the striking hero and Caroline Munro... well, words cannot do her beauty justice, she's simply stunning. It was originally intended to be a series featuring these characters but sadly they never materialised.
Incidentally, whatever happened to the planned Hammer revival that was quite big news a few years ago?