I’m solidly impressed with the WPMU Plugin Commander. One thing that seemed odd to me about WPMU was that I either enable users to have plugin control, or NO ONE (not even the site admin) has the ability to enabled/disable plugins (without a lot of hacking).
This plugin provides a control panel where I can globally enable/disable plugins, set plugins to be auto-enabled for new blogs, and give users the ability to enable/disable only selected plugins.
The perfect scenario is, I want to auto-anable Akismet for my users, so they get spam filtering on comments. Also, I want them to have the ability to try out other various plugins, but don’t want them able to turn off Aksimet.
I’ll echo the sentiments of others I read when discovering Plugin Commander, “this functionality should be in WPMU core!”