In an article called 'Why Gears Of War Costs $60' the Forbes magazine analyzes the cost of selling a game like Gears of war.
Not a surprise, but more than a half of the money is not for the developer studio.
More info here: http://www.forbes.com/2006/12/19/ps3-xbo x360-costs-tech-cx_rr_game06_1219expensi vegames_slide_2.html?boxes=custom&thisSp eed=20000