I’ve just discovered the new ajaxified, PHP-based MODx Content Management System. It looks and feels great (test it here!). If there wasn’t any need for a dedicated admin interface (i.e. instead, content editable in-place for privileged users), it would be even more userfriendly. Maybe that’s the next step to take?
Another not-yet-ajaxified but nonetheless cool CMS (JEE based, supports JSR-170) I already mentioned before: Magnolia CMS (live demo, currently out of duty).
Further, a nice JEE based Open Source DMS/CMS/ECM supporting JSR-170: Alfresco.
For this site, I might switch to MODx instead of keep using WP (which basically still fights with the same problems it always did). The more as I’ve been dealing with AJAX professionally for a while now (but focussed on JEE as the enterprise server platform). As a DMS, Alfresco would come in handy. Now all I need is enough spare time to realize my plans ;)