Not seen 3, I think Donnie Darko is way, way overrated; its an entertaining film, but it gets far more than it deserves imo. Matrix should be maybe 9 in such a public demographic, it wouldn't come in my top 10 for sure
. The absense of Brazil is not a shock and understandable given its hardgoing nature. Episode IV at number one I think is inaccurate, people will have voted based on the star wars trilogy, rather than the first film in isolation. I think Empire is the clear 'better'. They are tied on score I suppose.
X2 in the top xyz is laughable, its an okay film, but not great.
Some of the stuff I wouldn't put in scifi though... night of the living dead, although understandble, I'd say should be classified under horror rather than scifi, unlike Alien, its scifi nature its really as present or important. A purest would have to strike that one off the list. I'm glad to see truman show mentioned, I really liked that movie and it is one of the essential sci-fi movies I'd list given 50 movies.
I think that list is surprisingly 'good', given the fact that the imdb "I'm a tool" mainstream userbase have voted for it.
Stuff like Barbarella are too culty to be highly rated.