Lots of minor ones but here are the more major ones...
One Life to Live (got hooked in the early 90's when i heard how they were placing a lot of emphasis of socially relevant storylines and bringing in people from outside of soaps to do some innovative things with it - movie producer as exec producer, novelist as head writer. Eventually that regime left and stopped watching in mid 90's but then that head writer came back to the show in 2003 and i started watching again and got hooked again. He was eventually replaced with probably the worst head writer in the show's history but she has been finally been replaced with a guy who's been on the writing staff for 11 years and was a huge fan before that and it's amazing how much he's turned the show around considering the mess he's had to clean up. Given enough time i think he may turn out to be the show's best HW! Too bad the writer's strike will probably mess up this progress though!)
Twin Peaks - definately need to get the recently released complete series gold edition box set when i can get a cheaper used copy.
Ugly Betty - just recent. I tend to not like watching a sequel of a movie if i haven't seen the original first and watch a tv show in the middle, so i only just started watching now that it's on DVD and even though i knew it was something i would really like, i'm even more impressed with it than i thought i would be.
Pie-in-the-face type slapstick humor. This includes everything from Three Stooges, Laugh In (which is great on many different levels), You Can't do That on Television, etc.
Comics: Peanuts, Doonesbury, Foxtrot, Boondocks, Calvin & Hobbes
Music: #1 obsession is Eurythmics and all related solo projects (Annie Lennox solo, Dave Stewart solo, Tourists, Platinum Weird, Vegas, Spiritual Cowboys, etc) - this is the one that i will go crazy collecting trying to get hold of everything i can.
Runner-ups where i don't collect everything but most stuff they put out: Pet Shop Boys, Depeche Mode, Shakespear's Sister/Siobhan Fahey
and several other fave bands on a lesser scale: Duran Duran, Chris Isaak, Beloved, Travis, Cyndi Lauper, and probably a couple that have temporarily slipped my mind as i'm typing.
But Jim Henson/Muppets are #1 (with maybe E'mics a very close second)