2.5 brought many great UI changes, but a few seem unfounded and, in my opinion, were steps backward. I’ve never been a fan of left-aligned interfaces. This plugin resets the interface to the center of the window. All proper credit to “Remove Max Width” by Dion Hulse – http://dd32.id.au – all I really did was regress and modify some CSS…
This plugin is available for download to be used on your WordPress self-hosted installation.