http://en.wikipedia.org/wiki/They_Live
http://www.imdb.com/title/tt0096256
I caught a couple minutes of it on tv probably almost two decades ago, and it made an impression on me, then I forgot about it. I occasionally remember it, and decided to look it up. Googling it was pretty easy, I just googled for "guy finds sunglasses that let him see aliens" or something.
I think I'm going to watch it, in all its probably cheesy glory.