Are you trying to customize the WordPress dashboard across all sites on a WPMU or WP3 multi-site network?
Most plugin solutions for this operate on a per-blog basis, which means you have to configure each site manually. Most code snippet solutions are outdated, and many get things like the Recent Drafts widget wrong. Recent Drafts is a “side” meta box, not a normal one, and a lot of scripts miss it entirely, so it persists even after everything else is removed.
White Label CMS looked promising but requires per-site configuration, which is a deal breaker on a large network.
The Incsub remove dashboard widgets plugin was the closest, but it does not remove all widgets. I updated it to catch everything, and made it compatible with both WP 2.9 and WP3.
Drop it in /wp-content/mu-plugins/ and every new blog created on the network comes up with a clean dashboard, no configuration needed per site.
Why You Might Want This
Combined with the New Blog Defaults plugin, Admin Menu Editor, and Dashboard CMS, you get a completely configured backend for your clients on deployment, without touching each site individually.
Installation
Drop the plugin file into /wp-content/mu-plugins/. It auto-activates network-wide.