I'm not sure but I think the $100 million doesn't include marketing:
http://www.gamesindustry.biz/articles/gta-iv-most-expensive-game-ever-developed
It probably includes stuff like licensing of the songs though.
EDIT - another link:
http://www.timesonline.co.uk/tol/news/uk/scotland/article3821838.ece
"It's like making a theatre production, a few movies and an album all to fit into one package,' he says. He hasn't a clue how much GTA IV has cost to make but hazards a guess at $100m. About 1,000 people have had a hand in developing it. The perfectionism Houser and Benzies demand of their teams is astonishing. For GTA IV, time-lapse cameras were set on rooftops in New York to capture the correct intensity of the rain. Over 100,000 photographs were taken on location."
My Mario Kart Wii friend code: 2707-1866-0957
