What memes are common in alien landing movies?

I was watching a movie the other day, in which aliens come to earth and place giant robots as sentries over the cities of earth while their ambassador who is looking for some reason to grant clemency to the human race is hounded by the authorities.

This move, I kid you not, is, “The day the Earth STOPPED,” a seemingly blatant ripoff of “The Day the Earth Stood Still.”

Anyway, there are a lot of convential elements common to these two movies, and a lot of other “alien invader” movies. Novels, too. I’d like to come up with an exhaustive list.

Just to start it off:

Aliens speak unemotionally and eschew the use of contractions.
“This is just the advance group.”
Large hovering objects reveal the invaders plan, giving earthlings time to do something about it.
Every act of resistance requires great personal risk of the main character.