heh, Scarface is overrated. Pacino did way better in Scent of a Woman. Anyways here's my list.
comedies - Blazing Saddles, The Producers (original), Animal House
dramas - Citizen Kane, American History X, The Deer Hunter, Rushmore, SLC punk, Raging Bull, Taxi Driver, 12 Angry Men
horror - Vertigo (James stewart was nothing short of amazing. Especially compared to the horrible horror flicks out nowadays. I'll never forget the first time i watched this film. The suspense almost made me cry at the end.)
Many people would put some more Zemekis/Spielberg/and Hanks films on there top lists. I feel that Hanks is overrated nowadays. Spielberg turned war of the worlds from a classic into a horrible remake. Few realize that Vanillia Sky was a remake of a foreign film titled "Open your eyes". If you get a chance, check that out. The foreign actors make Cruise and the american cast look like newb actors.
Few people realize the comedic genius of Mel Brooks. Blazing Saddles has the highest laugh per minute (lpm) ratio of any movie ever made.
This is my top list.