I was going to go with War Of The Worlds but then realised those aliens would just get swine flu'ed to death as soon as they arrived in London
So my vote was cast in favour of the martians of Mars Attacks. I always wanted one of them lazer guns. And think about it, with these ones we can hit back straight away and use their ships to invade Mars. Expand the human empire muh huh huh huh huuuuuuuuuu