I haven't seen 'South Park' or 'Shaun of the Dead'; not sure if I've 'Airplane!' (must have been many years ago if I have) so I'm not in the best of positions to judge, but certainly I think 'Holy Grail' is better than 'Life of Brian' (and both are much better than the decidedly hit-and-miss 'Meaning of Life'. 'Princess Bride' comes in at only 46 - should be a long way higher up, IMO, as should 'Some Liek It Hot' (currently at 16).

For anyone who's interested, the results are here: channel4.com - 50 Greatest Comedy Films vote from channel4.com/film