Simpsons (haven't watched in a looooooooooooong time)
King of the Hill
Real World / Road Rules Challenge
Malcolm in the Middle (used to watch all episodes, then just turned to catching a few here or there)
Friends (stopped watching around season 3 or 4)
Heroes
Desperate Housewives
Grey's Anatomy (this and DH were wife shows, and she even got sick of them)
Heroes is probably the only one that I gave up for sucking. The rest i just kind of got bored with, or didn't have time to watch.
LOST (oh wait, maybe i can make it 2 more episodes...
)
Gave up on South Park when I graduated from college (for about 3 seasons), but then got back into it.
probably more but that's all i remember off the top of my head.