The 'black and white' issue of morality in games come up a lot. A lot of reviewers complain about it as it basically "are you a saint or a baby eater?" kind of deal. Games like Dragon Age Origins are good as there is no 'moral bar' there is nothing saying you are good or evil, its up to you to measure your own actions. Thats one thing i disliked about Fallout 3, I had used up all my money helping people. I stole one bottle of water, which I really needed to heal, and got negative karma for it.
In games I usually play it three times throgh, one being good, one being bad and one being me, sometimes its more fun being evil (anyone who played KOTOR knew how funny it was to be evil with HK-47 in toe). I play 'chaotic good' for my 'me' play through, you dont make compromises and follow your code to the letter, kinda like Rorshach from Watchmen.
I like games that have moral choises in them though I wish they werent so extreme (ie Dragon age 2, side with fanatic A or fanatic B). I feel that being evil in games doesnt translate into being evil in real life though.
In games like Grand Theft Auto, you can go on a shoting spree, killing hundreds of innocents and police men and suffer no negative reprocussions. In games like Dragon Age, Oblivion, Fallout etc, when you do something evil it has reprocussions, certain factions will become hostile, certain people will charge more in stores and your can bet that theres gonna be a group out for your hide for revenge etc. Just like real life being bad has reprocussions just as sometimes being good has its negative sides.