A little known fact: In November 1991, during my GCSEs, I watched "Top Gun" 17 times. I'm an absolute fan of "The West Wing" (now available on DVD). That aside, I prefer to categorise my favourites as follows:
(examples are not exhaustive)
World
e.g. Zhang Yimou's films, "A Beautiful Life"
Beautiful
e.g. "The Godfather"s, "The Red Violin", "Crouching Tiger Hidden Dragon", "Kill Bill"
Inspirational
e.g. "Chariots of Fire", "The Devil's Advocate", "Schindler's List", "The Soong Sisters"
Old
e.g. "Guess Who's Coming To Dinner" - one of my dad's favourites too! He's the one who first introduced me to "Fawlty Towers"
Cool
e.g. "The Fast & the Furious"s
Chick flicks
e.g. "Clueless", "Legally Blonde"s, "Bridget Jones Diary", "Maid in Manhatten"
Espionage
e.g. "Hunt For Red October", "Mission Impossible", Bond films
Audrey Hepburn
... Of course, this list becomes obsolete if my talented boyfriend ever makes a film.