I've always wanted to ruin one of these threads.
Hey, everybody! In Star Trek XII, SNAPE KILLS DUMBLEDORE! BAM! You're all done!
Seriously, though. Yes, I was spoiler-free for XI and very, very happy about that. Even though it meant I had to abandon the BBS for about two months before the movie. I did watch the trailers -- obsessively -- but that mostly served to heighten my anticipation.
By contrast, when Nemesis was on the eve of release, I not only avoided all spoilers, I would even change the channel when a TV ad for it came on. This went a little bit overboard. However, it was very worth my while to have avoided the entire pre-NEM hatefest that apparently went on online, because it meant I could go into theaters at midnight on 12/13/03 with a completely open mind. And, you know what? I loved it. Nemesis is a wildly underrated movie that, while flawed, had all its flaws amplifed a hundredfold by a hostile fandom that got hold of a script before its release.
Which is why it's vital that XII have the same tight security as XI.