I was wondering about this same thing (except with violence and killing, not magic) when playing Half Life 2 a few months ago. And then yesterday I was playing some penguinz game where you tote all kinds of guns and what not and kill other wintery creatures. Still not sure where I stand (perhaps it's just a desire to not let go of this fleshly fun), but what about a game I was reading about on gamedev.net recently? These indie developers are attempting to make an exotic game where all your goals are sex oriented. What about those rape games that were in Japan recently? Should we play those even though we don't believe in it? Is this even a gray area? Or do we make these things gray areas because we have a very difficult time letting go of certain things for Christ's sake? Then of course the discussion can branch off to tv shows and cartoons like futurama etc., and the kind of impact we have AGAINST Christ when non-believers hear us say things like "oh oh... you shouldn't be watching Simpsons... it's bad" etc., or the kind of impact we have AGAINST Christ when we say "oh no it's ok if you're mature enough to understand the difference, but it's not ok for my 3 year old". Is it REALLY ok for you if it's not for your 3 year old?
Anyway to me it's all a really gray area, but I'm pretty sure I've done this to my self for my sake, not for His (as I shoot penguins and hide the game from my kid). Good luck with this discussion... there is the potential for some pretty conflicting opinions especially when it comes to matters of the flesh that we don't want to admit are such.
Maybe we could all pray for the Lord's guidance for each other about this and to recognize and be willing to see if and where we are at fault?