If you’re a user of Wordpress, you should probably always upgrade when a new version comes out for security reasons.  However, with the new release of Wordpress 2.6, there are three features that really stand out for me — in addition to the security enhanced goodness and all the other new stuff, that is — and these are “versioning”, the way they’ve cleaned up the plugin page, and “turbo”.  The latter two things are small, but they’ve meant a great deal to me, in terms of my work flow {”Turbo”, of course, refers to Wordpress installations now using Google Gears to speed things up (it is now pretty snappy)}.  “Versioning”, however, is a really nice feature, which allows you to go back to different draft versions at Wordpress is automatically saving drafts.  If you find that you do think about and revise posts repeatedly (as I sometimes do), it gives you a lot of lattitude to recover thoughts and ‘forks’ in your arguments that you may have deleted and want to get back to.

Addendum: One extra cool thing is that when you browse themes, and click on a theme, Wordpress 2.6 previews that theme with your current content “configuration” of pages, posts and so on (and literally, the content in your Wordpress database).  Very slick.