This is interesting... I took my Top Movie List, which had over 100 titles and was a mess, and used the advice from this blog to randomly select a top 10 from those titles: http://blogs.indiewire.com/pressplay/video-sight-sound-film-poll-ignatiy-vishnevetsky-on-how-to-make-a-random-top-ten-list
Strangely enough, the list turned out great! This list is almost identical to the list I would have made as a teenager (if you replaced Forbidden Planet with something by Kurosawa or Lynch, that is).