A question, does it make a difference what order we place the movies in? Does my #1 pick carry more weight than my #20?
It's just me, but I think I'd favour a system where pick 1 is worth 20 points and pick 20 worth 1 point (or perhaps a less extreme variation)... That way if someone happens to REALLY like something that's pretty obscure it won't necessarily get dropped from the list just because they're the only person who has seen it, and thereby the person won't just omit the film outright knowing it'll be an irrelevant vote (ie it ensures a submission that's truer to the members actual opinion).
Example:
Member X's alltime favourite movie is ObscureMovieX say, and nobody else has seen it.
Member A & B's 20th picks are both Charlie and the Chocolate Factory.
Boom, ObscureMovieX won't see the light of day. Is that right? Is that the most accurate representation of the collective's beliefs? I don't honestly know, but I think it warrants some thought.
Perhaps a milder weighted voting system like 1-5 worth 4pts, 6-10 worth 3pts and so on. At least for the first round so people feel that their opinions might make the top 200 and get, at the very least, a glancing acknowledgment.
Just thought I'd throw that out there.