This Greasemonkey script expands the video to occupy more space and puts the comments next to the related videos and the video description in a small sidebar. To install the script, you need to have Firefox and the Greasemonkey extension.
For a YouTube look in Google Video, you don't need a script.
P.S.: Did you know that Aaron Boodman, who created the user script manager Greasemonkey, works at Google on client-side scripting? "I would often encounter a Web page that didn't work the way I wanted. And I'd think to myself, I could easily fix it if I could just run my own JavaScript in the page," explains Aaron why he built Greasemonkey. To learn how to write your own scripts, there's a free book called Dive into Greasemonkey.
