I sure have! More than once, actually.
I have seen it once.
I have never seen it.
I watched it recently for the first time, mainly to prep for The Day the Earth Stood Still remake.
My interest in the remake is high, so I plan on watching the original soon.
I plan on rewatching the original, mainly to get the idea of the remake out of my head.
I have no interest in the original, or the remake.
I have no sci-fi opinion.