Change the [L] player size to 1280x750 (30px for the controls) from 1256x737. Thanks to cra3y on userscripts.org for spotting this.
Version 2.4.0: The script now partially reinitializes when YouTube loads a new video via AJAX. To be able to use YouTube's events for this, the script is now added directly to the end of the page's <body> tag as a script element. Huge thanks to http://userscripts.org/scripts/show/153699 for showing how to respond to YouTube loading videos via AJAX. Tested with Chrome 28.0.1500.95 m and Firefox 26.0a1 (GM/Scriptish). Version 2.3: Update script to be compatible with YouTube's changes. Fix the playlist bar's width that, I think, has not been affected by the script properly for a while. Tested with Chrome 28.0.1500.95 m and Firefox 26.0a1 (GM/Scriptish). Should work on both the regular and the new centered YouTube layout.