If you take the view that Art is the process of deliberately arranging elements in a way to affect the senses or emotions, then I would argue gaming is one of the most artistic fields of endeavour - as its interactive nature allows game developers to directly access these feelings in ways that static or non-interactive mediums cannot.
However, if you believe my good friend Dictionary.Com, then art is:
the quality, production, expression, or realm, according to aesthetic principles, of what is beautiful, appealing, or of more than ordinary significance.
In which case only the very best of anything will ever be art, regardless of medium. You can have a painting, but only a beautiful or significant or appealing painting will be art. Likewise with games - Bioshock (as it has beautiful art direction) may be defined as art, whereas a Pong-knockoff would not.
However, if you believe my good friend Dictionary.Com, then art is:
the quality, production, expression, or realm, according to aesthetic principles, of what is beautiful, appealing, or of more than ordinary significance.
In which case only the very best of anything will ever be art, regardless of medium. You can have a painting, but only a beautiful or significant or appealing painting will be art. Likewise with games - Bioshock (as it has beautiful art direction) may be defined as art, whereas a Pong-knockoff would not.