It has not been long ago when I upgraded this WordPress installation. There is now the update to WordPress 2.3 avaiable. For me the most interesting new things are canonical URLs, update notification of new releases of WordPress or of plugins that are used and native tagging support.
Since some months I have been using Ultimate Tag Warrior but have not very happy with it and in my opinion it was not working properly all the time. So I was looking forward for the native tagging support in WordPress 2.3.
As the last time the upgrade was easy and fast. Moreover there is an option import Ultimate Tag Warrior tags into the new native tagging structure.