The new channel editor is more simple to use and you can preview the page after you make some changes. "Rather than take you off to a separate page, we figured it'd be nice if you can edit your channel... in your channel! So, take a peek up top, you know, near that big grey bar. Just below it, you'll see some extra buttons, "Settings", "Themes", "Modules". Check those out! Also, in the upper-right corner of each section of the page, you should see a little "edit" button. Those let you customize the part of the page you're looking at. Some sections can be customized more than others, of course."
Besides the visual refresh, the new channels include a player that helps you view recently uploaded videos, favorites, playlists without leaving the page. You can choose between 10 predefined themes or create your own theme.
YouTube created a blog where you can find more information about the updated channels. And here are some upgraded YouTube channels: mnathanielc, Slyth66, missxrojas.
{ Thanks, Pascal. }