Let's see ... This is tough, I barely watch television at all, and I especially don't watch anything outside of networks, Comedy Central, and Cartoon Network. So surprise, surprise ...
This is in order of how much I'll go out of my way to watch it. Lower on the list means higher probability of it just being DVR'd to watch when I get a chance.
1.) HEROES - I met Adrian Pasdar (Nathan)! Cool guy. And I'm in deep, forbidden love with Masi Oka.
2.) Boondocks - I laugh myself shitless every episode.
3.) Naruto/Bleach (Shut up! I watch fansubs of these as they drop from Japan. Naruto shows up on Tuesdays and Bleach shows up on Thursdays, so I pretty much just group 'em together, but I've never missed an episode. Honestly, I fucking hate these shows. They're terrible. BUT I CAN'T STOP WATCHING. O_O ... Must ... Save ... Sasuke ... Must ... Save ... Orihime ...)
4.) Family Guy/American Dad (I like A.D. less, but they're on at pretty much the same time so these two are just grouped together).
5.) South Park (It'd be higher than F.G., but lately F.G. has seen me getting hysterical more thoroughly, plus it lost a few points with that Oprah's snatch ep).
6.) Futurama (I've seen every ep, memorized every song, memorized nearly ever line. It'd be #1 if there were new ones --- end of March, baby!!!)
HONORABLE MENTIONS (of course, this is only listing things that still air or have recently stopped airing, syndicated or otherwise):
Shin-Chan
King of the Hill
Samurai Champloo
Cowboy Bebop (favorite anime ever)
Scrubs
Robot Chicken
Aqua Teen Hunger Force
Simpsons (old ep's)
Smallville (it's sucked lately, but I'm still devoted T_T)
Spongebob (older eps, where they did the Ren & Stimpy-like painting stills)
Ren & Stimpy
Dirty Jobs
How It's Made (Disc. Channel)
Mad TV
King of Queens
Two and a Half Men (I HATE myself but if it's on I won't change the channel)
Attack of the Show
Ninja Warrior
X-Play
Fresh Prince
... Lordy, too many to list, really o_o
Funny how many of us have the same tastes :D
