why use Drupal for city government?

Jeff Walpole covered a lot of information in this article: http://govfresh.com/2010/02/5-government-sites-using-drupal-effectively-...

I would use the more generalized arguments of open source, which can apply to any software from things like openoffice to drupal, and also use some high profile sites to demonstrate that Drupal isn't some toy, but an actual viable opportunity for government to save money. Money is a big thing for government and the first and last points I always make when talking about opensource. In the middle, talk about the reliability and market penetration. Governments don't like to be guinea pigs, so tell them the White House uses Drupal.

There was an awesome presentation given at the Lullabot "Do It With Drupal" back in Dec 2009, where Arizona State University (http://groups.drupal.org/arizona-state-university), talked about their entire University "buy in" came when the Librarians fell in love with Taxonomy module (if I remember correctly). The session also had good info from Columbia and MIT, but the ASU people really had an amazing talk about a massive institution with lots of sub-groups, and how they architected their implementation - and it all started with making Librarians happy. :)

Here's a link to ASU's Jeff Beeman's page from DIWD 2009:
http://www.doitwithdrupal.com/speakers/jeff-beeman

I don't know if you have seen this post or not about OpenPublic: http://www.opensourceopenminds.com/openpublic it probably has a lot of what you might be looking for.

Maybe this article can help too?!

http://govfresh.com/2010/05/gov-2-0-guide-to-drupal/

Article from above in German - just in case ;)

http://www.segments.at/government-2-0-leitfaden-zu-drupal