'I Married A Monster From Outer Space' doesn't stray too far from the run-of-the-mill 50s sci-fi that has become a pop-culture cliché, but it does distinguish itself enough to almost be regarded a classic of the genre. Real thought has clearly gone into it, to offer audiences at the time something more substantial than the usual B-grade monster scares, and it's for this reason that, over sixty years later, it…