Talk Xbox - Large Xbox Forums with thousands of members. - http://www.talkxbox.com/forum
Xbox Forums - News about popular games and communities, articles and interviews about what's happening on these boards and information about the official Xbox site. - http://forums.xbox.com/
GetXbox Forums - Xbox, Xbox 360, Xbox live, Xbox Downloads, Xbox Articles, Xbox news, Xbox games, Xbox reviews, Xbox forums. Keeping gamers informed with up-to-date news and articles. - http://forums.getxbox.net
My Xbox - A community for owners of the Xbox console and Xbox Live. - http://www.myxbox.co.uk
Xbox Impact - A forum for fans of the console. - http://www.axisplay.com/forums/
X-Factor Forums - Discussions on general news, technical issues, and popular games. - http://xfactorforums.proboards18.com/index.cgi
XBLTeams.com - Games and Xbox Live topics. Also hosts tournaments and forums for clans and teams. - http://www.xblteams.com/
Xbox Central - The system, Halo and other games. - http://xboxcentral.proboards10.com/
Xbox Clubhouse - Discussion forums. - http://www.xboxclubhouse.com/
Xbox Discussion Forums - Xbox, registration required to view posts. - http://wisecup.ionichost.com/phpBB/