Apparently Serenity has been voted the best scifi film on a SFX magazine poll, beating out Star Wars of all things. The BBC has even published an article on it...
http://news.bbc.co.uk/2/hi/entertainment/6517155.stmThe original article:
http://www.sfx.co.uk/page/sfx?entry=lord_of_the_fireflies While I love Serenity, I don't think it's the best scifi film ever... not while there's other things like Blade Runner or The Matrix in the running. Personally I think The Matrix is my favourite scifi film ever and definitely one of the most influential films of the last decade. Never has a movie before or since taken hold of me as that movie did the first time I saw it.