There's a bunch of high-power game designers talking about the most influential games of all times here:

http://idt.gatech.edu/projects/gamemorph/overview.html

Although they list Space Invaders in the sidebar as one of the most influential games of all times, NONE of the household name gaming gods seem to remember it at all. I must be getting old, but Space Invaders was video games in the day. Sure, there was pong, frogs and a couple of crude driving games before Space Invaders, but in the past I remember, Space Invaders was on the news, in the papers, and in every arcade, movie theater, and pizza joint around. It pretty much kicked pinball into a back corner, from which it's never fully emerged.

A lot of these answers just seem to be of the, "go away kid, you bother me." sort of nostalgia. Still, even of the people who tried to answer seriously, memories seem pretty short. The biggest insight revealed by this project seems to me to be the flawed methodology of the project. Nevertheless, I read every word on the page and find it all quite fascinating. Useless perhaps, but fascinating all the same.