Art

: the quality, production, expression, or realm, according to aesthetic principles, of what is beautiful, appealing, or of more than ordinary significance. (From dictionary.com)
See, art does have a definition.
From that definition, its easy enough to see that yes, everyone's opinion may differ, but one thing remains true for art; it stands out.
And if you want to resolve this debate, you have to start comparing video games to other VIDEO GAMES. Video games are obviously entertainment,like books and movies, but what this debate really asks is if games are all the same, or hold the same entertainment value. I believe the original poster already answered this, and Im 99% sure all of you can too.
Kurokami said:
However the 'Games aren't art' comment implies games cannot be art, that's what the argument is about.
'Are not' does not equal 'can not'. So you cant FAIRLY make an implication, one way or the other.