Whatever happened to the public square plan for downtown? Detroit (yes Detroit) did it a year ago and it has been a big hit. Copuware even moved its company headquarters of 4000 employees from the burbs next to the square.
http://www.pps.org/info/newsletter/december2005/motor_city
Here is the site plan. I think its character as a central meeting place and activity center rather than as a green "open" space is the key to its success. http://www.campusmartiuspark.org/park_siteplan.htm