Vik, you've seen ESCAPE FROM LA but not ESCAPE FROM NEW YORK? Gotta see the first one, man; if you are a Carpenter fan, ya GOTTA see NEW YORK. Classic stuff.
I love THEY LIVE. I saw it in theater when it came out and have rented/watched on TV numerous times since. It's the essence of Carpenter - great entertainment fun with a message, but you can take or leave either as your personal taste dictates.
I remember being skeptical about casting Piper, but upon watching, that role was made for him. And yes, the fight scene is iconic.
One thing's for sure: you'll never look at advertising the same way after watching this movie.