All my favs are listed. Outside of car channels I watch the following:
http://www.youtube.com/user/Suspicious0bservers - "Star weather" daily report on solar activity, astronomics, and global weather. Posted every day, you get really good insight into what's going on around us through publicly-accessible government sites.
http://www.youtube.com/user/EdgunUSA - When I had rabbits in my backyard a couple of years ago, I fancied myself a suburban hunter with an air rifle. YouTub'd help vids and stumbled across this site. Seems like a really good guy who's passionate about humane varmint hunting.
EPIC RAP BATTLES: http://www.youtube.com/user/ERB
I'll also add that we have no cable, no satellite TV...with internet and smart TVs (Netflix, Plex, Amazon), iPods, and laptops, I get 100% of my content for a few bucks a month.