@ Puggo: Very much so. That's maybe one reason why Serenity won. It's pretty much just as well-acted, written and visually impressive as ESB in a lot of ways, and I think people take it as representing Firefly as a whole, so it's not that one is necessarily better or worse, it's just what is more relevant? ESB is 30 years old and not quite in the "hard" sf style IO9ers go for, while Serenity is relatively new and more in keeping with modern tastes. That said, ESB made it all the way to the finals and 2001 made it to the semi's because really good films still get appreciation by many people even when they are old, they just don't retain quite the same level as when they were newer and more stylistically (and thus experientally) relevant. Blade Runner and Terminator also made it to the semi's.
It's actually a bit of a surprise that Serenity managed to beat all these, but like I said, you have to consider the tastes of the people voting and Serenity has a really intense internet fanbase. As soon as people on Serenity forums start getting the word out to vote it to the top, it has staying power. Such as here: http://beta.fireflyfans.net/mthread.aspx?bid=11&tid=48015
and here: http://melbournebrowncoats.com/2011/03/17/vote-for-serenity-in-io9s-march-movie-madness/
Star Wars has similar advantages. TF.N is always reported on polls to go support. Maybe they just missed this one.