had plenty to say to that, but I also resigned myself to the fact that not everyone would agree with me. Like the poster who findsCitizen Kane boring, I myself cannot sit through Gone With the Wind. However, give me Casablanca or any Frank Capra movie, and I will be enthralled for hours.

By no means an oldie, I think the film "Gandhi" is destined to be a classic.  The array of emotions I experienced while watching that movie can't be adequately described!  It was moving, awe-inspiring, touching, loving, comical--it had everything and was pure entertainment at its height!  I'm told David Attenborough produced it.  He did a spectacular job!

I think, as others have mentioned, that it has to have a timeless quality to it-not just the film, but also the message and/or theme.  In addition, though, it should be revolutionary in one aspect or another: I find Citizen Kane, rated by many as the greatest film of all time, to be extremely boring, but it basically revolutionized film-making into an art form.  Check out AFI's Top 100 films and some of the films are rather surprising because of some new aspect of film making that was introduced (The Wizard of Oz, Star Wars, etc.).

In-depth character study films can become classics as well, such as Raging Bull.  These films really help the viewers understand the struggles and motivations of the main characters.

I agree...it's much the same of what categorizes classic literature.  It stands the test of time, appeals to a wide variety of audiences, and deals with timeless and universal issues such as greed, love, revenge, etc.  Many teach one or more lessons, as well.   Some of my favorites include (but are by no means limited to) Somewhere in Time, The Wizard of Oz, and the Shirley Temple films.

Classic films are films that are "of lasting worth or timeless quality."  They are well-made with great acting, music, and dialogue.  Their attention to historical details, costuming, and scenery are well thought out and done right.  Classic films are believable--enough so that people actually become absorbed in the movie to the point they feel they're part of the story.  Some classics deliver a poignant message that evokes strong emotions in the viewer, making them want to do better and be better people. 

Take a classic like "Gone With the Wind"--the acting is great, the music is spectacular, the scenery is breathtaking, the historical Civil War battle scenes are both authentic and heart-wrenching--though based on a novel, the story is believable.  It portrays to the viewer a multitude of messages:  that war is cruel and ugly, that love transcends all things, that jealousy rips people's hearts out and drives them apart, and that out of adversity's blackened ashes rise true heroes and heroines.  We laugh; we cry; we are inspired; we are angered; we are entertained!

That's what a classic does! 

It's rather like literature isn't it? Classic films will endure, and they will inspire, and they will keep people coming back to watch them. Interestinig thing to consider--how many "classic" films are based on "classic" literature? For example: Cat on a Hot Tin Roof.

To me a classic film is one that maintains its appeal through the generations; one that my parents found interesting, I find interesting and the younger generation finds interesting.  So, it of course has to be an older film. Next it has to have a message that is some what universal; that is, speaks to people no matter what age.

Great question.  Personally, I think to be considered a "classic" in my book, a movie has to meet a couple of key tests:

1)  Great dialogue - special effects will look outdated at some point, and action is just eye candy, where great dialogue and the relationship between characters stays with you, as do the lines and quotes that struck you throughout the movie

2) Stands the test of time - is popular with the generation after the one that first watched it, and the one after that.  Movies that are believable, well written and acted and meet criteria #1 will be popular for decades and with different age ranges.

3)  Offer some kind of revealing or profound commentary on the subject of the film or the time frame in which it was made, so that the movie becomes more than just a movie, but a reflection of society as well.

There's probably more, but this is the first time I've really thought about it.  Interested in what others think...

A classic film, to me, is one that achieves an artistic vision (demonstrating concern with theme and story, but critically focusing on a means of conveying a theme) and also entertains, captivates, and demands re-viewing. 

Some classics that come to mind: Network, The Conversation, Persona, Failsafe, The Empire Strikes Back...

As with books, there are many definitions of classic.  Some films and books are described as instant classics, which seems to be a contradiction in terms.  Therefore a classic is not just a movie that can be watched and enjoyed by generations, and holds meaning.  A classic is also a movie that we see now that we predict will have those properties.

Classic films, like classical music, art, and literature, are replete with meaning, significant dialogue, techniques, and superb actors.  There are many different levels at which these films can be viewed.

One movie that brought three actors Academy Awards and was a great satire is the 1975 film Network.  But, what few, if any, viewers knew at the time was how prophetic this movie was. Now, in 2010 the movie hardly seems a satire; at any rate it is not exaggerated.  This ability of a film to transcend a time period seems also a measure of "a classic."

Whenever students enjoy an old film and comment that it is "really good," someone invariably beats me to my remark:  "It's a classic!"

I would agree with mshurn's assessment. It's rather like literature isn't it? Classic films will endure, and they will inspire, and they will keep people coming back to watch them. Interestinig thing to consider--how many "classic" films are based on "classic" literature? For example: Cat on a Hot Tin Roof.

I read somewhere  that a "classic" anything was at least 100 years old, but the term clearly has a wider application. The commonality, though, is that a classic withstands the test of time; it lasts because of its enduring appeal, generation after generation. In terms of film, a classic must combine excellence in many respects of cinema, but something else is involved, I think.

A film classic is more than an excellent movie; it is an excellent film that explores universal truths in a unique way. The "unique" elements of a classic film might include photography and scenic design (Orson Wells' Citizen Kane), or a new way to present an old genre, such as the incredibly suspenseful movies of Alfred Hitchcock. Much of Hitchcock's success in creating suspense also involved new and creative uses of the camera. Sometimes a film classic is a movie that breaks new cultural ground by telling a story previously untold in film--or by presenting a compelling vision of the future.