Hate the omissions, but love the picks
All lists are redundant really, especially those trying to deal with something subjective such as the list of greatest movies ever made. Personal lists I don't think you can attack so much, a list of personal 100 favourite movies is something specific to that person, but 100 movies YOU must see before YOU die will always raise certain eyebrows. 
Yahoo, obviously struggling for hits got their editorial staff together to come up with such a list. They considered factors like historical importance and cultural impact and also films that they believed were the most "thrilling, most dramatic, scariest, and funniest movies of all time". The result is 100 great movies, barely any that I wouldn't call an absolute must-see classic. Of course some of the omissions are horrific. The short lack of movies from this millennium for starters and then the lack of Werner Herzog, the lack of North by Northwest, the lack of The Empire Strikes Back, A Clockwork Orange and The Shining (the list clearly favours only single or two entries from directors). But its still a good list. If you haven't seen any movie on this list, I highly encourage you to do so. Except, When Harry Met Sally... do you need to have seen that for some kind of life enlightenment? 12 Angry Men (1957) 2001: A Space Odyssey (1968) The 400 Blows (1959) 8 ½ (1963) A Hard Days Night (1964) The African Queen (1952) Alien (1979) All About Eve (1950) Annie Hall (1977) Apocalypse Now (1979) The Battle of Algiers (1967) The Bicycle Thief (1948) Blade Runner (1982) Blazing Saddles (1974) Blow Up (1966) Blue Velvet (1986) Bonnie and Clyde (1967) Breathless (1960) The Bridge on the River Kwai (1957) Bringing Up Baby (1938) Butch Cassidy and the Sundance Kid (1969) Casablanca (1942) Chinatown (1974) Citizen Kane (1941) Crouching Tiger, Hidden Dragon (2000) Die Hard (1988) Do the Right Thing (1989) Double Indemnity (1944) Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964) Duck Soup (1933) E.T. the Extra-Terrestrial (1982) Enter the Dragon (1973) The Exorcist (1973) Fast Times At Ridgemont High (1982) The French Connection (1971) The Godfather (1972) The Godfather, Part II (1974) Goldfinger (1964) The Good, the Bad, and the Ugly (1968) Goodfellas (1990) The Graduate (1967) Grand Illusion (1938) Groundhog Day (1993) In the Mood For Love (2001) It Happened One Night (1934) Its a Wonderful Life (1946) Jaws (1975) King Kong (1933) The Lady Eve (1941) Lawrence of Arabia (1962) The Lord of the Rings (2001,2002,2003) M (1931) M*A*S*H (1970) The Maltese Falcon (1941) The Matrix (1999) Modern Times (1936) Monty Python and the Holy Grail (1975) National Lampoons Animal House (1978) Network (1976) Nosferatu (1922) On the Waterfront (1954) One Flew Over the Cuckoos Nest (1975) Paths of Glory (1958) Princess Mononoke (1999) Psycho (1960) Pulp Fiction (1994) Raging Bull (1980) Raiders of the Lost Ark (1981) Raise the Red Lantern (1992) Rashomon (1951) Rear Window (1954) Rebel Without a Cause (1955) Rocky (1976) Roman Holiday (1953) Saving Private Ryan (1998) Schindlers List (1993) The Searchers (1956) Seven Samurai (1954) The Shawshank Redemption (1994) The Silence of the Lambs (1991) Singin in the Rain (1952) Snow White and the Seven Dwarfs (1937) Some Like It Hot (1959) The Sound of Music (1965) Star Wars (1977) Sunset Blvd. (1950) Terminator 2: Judgment Day (1991) The Third Man (1949) This is Spinal Tap (1984) Titanic (1997) To Kill a Mockingbird (1962) Toy Story (1995) The Usual Suspects (1995) Vertigo (1958) When Harry Met Sally (1989) Wild Strawberries (1957) Wings of Desire (1988) The Wizard of Oz (1939) Women on the Verge of a Nervous Breakdown (1988) The World of Apu (1959)