If you guys want probably the best "list" of top movies, its the Sight and Sound polls that they do every 10 years (the interview a large number of critics and a large number of directors, whose individual top 10 lists are compiled). I have seen quite a few of these lists, but by and large Sight and Sound's polls are considered far and away the best.
Here are the most current versions:
http://www.bfi.org.uk/sightandsound/topten/One of the nice things is you can see who voted for each film, and which films those people voted for. Some of the people annotated their list to say why they picked each film.
There is also a smaller poll of only UK critics regarding the best films of the last 25 years (done in 2002). Its a little more suspect (I doubt Yi Yi or Distant Voices, Still Lives will be on the list in ten years), but cool nonetheless:
http://www.bfi.org.uk/sightandsound/feature/63/