My guess is that they are going to be in the red big time. Even a bigger deficit than the '76 game in Montreal. I think security fears may have kept a lot of foreigners from coming to Athens but it is no excuse for the locals.
The IOC really wanted the games to be in Athens for the anniversary and pretty much handed the games to them.
"Athens organizers, in their rush to finish building some of the sparkling new venues, apparently didn't work as hard trying to fill them. And Greeks are proving to be selective about what they'll pay money to watch, despite ticket prices of as little as $11 US a seat for some preliminary competitions. That's led to some embarrassing scenes, such as Sunday when Williams played in front of only about 500 fans on centre court in the Olympic tennis complex."
http://www.tsn.ca/olympics/news_story.asp?id=95046