I'm married to the cable guy so we have every station under the sun available to us. I'm embarrassed to say that the TV is on in our house most the time. I like the background noise more than I do a silent house (which will put me to sleep). My son goes back and forth between watching his shows and having mine on in the background. He doesn't pay much attention to my shows but when his shows are on, it does give me a LITTLE break to do what I need. He's never sat in front of the TV mesmerized like "they" warn. Instead, he'll play, watch for a few, play, etc. If music's on he'll dance to it.
Besides Noggin, there's Sprout TV (great shows on), Nick in the morning, Nick2, and NickJr. Sprout and NickJr. always have toddler shows on. I also have a few DVDs of the Wiggles and I bought a used Bear in the Big Blue House Potty Training video (crossing my fingers!) but what I've found to be most helpful and educational are the Your Baby Can Read DVDs. They are pricey unless you find some on eBay used but my son learned a lot of words even before he could say them and he loves to look at the images. Even now at 19 months. They really do work and though he's not reading (I don't play them every day like I should) he has learned more from them than from any of the shows on TV, including Sesame Street and Baby Einstein. So that might be something for you to consider that would ease your guilt over them watching the "boob tube". Either way, I wouldn't fret too much about it.