The main problem with arguments like this is that people consistantly try to compare movies to games or vice versa, and that's the thing. You CAN'T compare them!
Why? Because video games are a form entertainment that completely rely on interactivity. Unlike movies where we just plop in a chair and listen to the characters and sounds, but what we mainly do is watch them (When was the last time you went to go see a movie and actually "interact" with it?).
In order for a movie to be a good movie, it has to have an interesting plot, equally interesting characters, smart writting, good music, genuinely funny moments (if the time ever comes), thrilling action set pieces (once again if the time ever comes), closure, and has to last a minimum of one and a half to two hours. A modern big budget video game not only needs most of those mentioned above to be good (maybe a little more on the action, but it also needs interativity, atmosphere, replayabilty, funtionallity, and has to last a minimum of eight to ten hours!
I'm not saying that one is a better form of art than the other. Infact, if someone does come out and say that, they're clearly talking out of their ass. I thought everyone knew art was subjective and open to opinion. Lots of people think that the glass pyramid in front of the Louvre in Paris is a brilliant work of art, but I think it's one of the tackiest things on the face of the planet. Lots of people think Six-String Samurai is a poorly written cheese fest of a movie, but I consider it one of the best films ever made.
However I will say that video games are and can be considered art. Anyone who has played Shadow of the Colossus, Beyond Good and Evil, Bioshock, and pretty much any game made by Suda 51 and Tim Schafer knows what I'm talking about. Just because video games are a bunch of jumbled up bytes, programs, and physics engines doesn't mean that they can't be art. If that's the case, then Casablanca, Citizen Kane, and Dr. Strangelove can't be art because they're just a bunch of moving pictures blown up on a wall. Bob Dylan, Johnny Cash, and The Beatles can't be artists because all they did was make amplified sounds played at different pitches. The Mona Lisa can't can't be a work of art because all that it is is different colored mastic compositions on a piece of parchment.