Removes the advert, bottom copyright notice, and user-comments. Resizes the related-videos, and Director-videos to fit on a 1280x1024 (With 4 layers of Firefox toolbars [3 default, plus one extra]).
I made it mostly because I find the comments on Youtube somewhat annoying/completely unconstructive, and it's far nicer to have everything on one, non-scrolling page.
Update : Sorted the video info page (was too long with directors videos, or expanded video-info), it now scrolls if the content is fairly long
Update 2 : Hid the "Try the beta version of this page" link, and some other promotional link in the footer and a few other things

Note : This theme only applies to URL's starting with "http://www.youtube.com/watch", it's technically a bug (since http://youtube.com/watch wont be updated).
But, I prefer it this way.. Why? If you want to read the comments on the page, simply remove the "www." from the URL and hit go - And your back to the original Youtube layout, including comments