RedFive said:
2001 is an easy contender for the greatest film ever made regardless of genre IMHO, but that doesn't have a huge, call-to-arms internet fan society like Serenity/Firefly does

This is exactly why. It doesn't surprise me that it was ESB vs Serenity in the end, because these have the strongest and most active fanbases online. In fact, the only reason the Serenity movie existed was BECAUSE of the online fans, just to put their strength in perspective. I'm sure ST made it pretty far up the list too because of fan community.

On the other hand, films like Planet of the Apes, 2001 and Forbidden Planet, which generally are in the top 10 sci-fi films of all time, aren't popular with grassroots fans. All this poll was is a popularity contest from the tastes of i09 users, and its no surprise that Firefly/Serenity did so well when you consider that. And again--being the runner up, ESB is definitely well loved over there, so I'm not sure what the outrage is.