I've seen the 1978 remake with Donald Sutherland. Very good and with a bad shocking end.
Invasion of the Bodysnatchers (1956)
The original "pod people" film. Although this was made in B&W, it was originally photographed in a wider screen ratio than the other two SF films above, which were projected at the 1.37:1 and 1.85:1 ratios respectively.