Well, I don't think there is anything beneficial about watching tv, but depending on the content and the situation, I don't think that it is necessarily harmful.
I am most against tv when it takes the place of other activities - especially being active. So dh and I already know that we will not allow the tv on after school. Dh spent too many wasted hours on the couch, and wished that his parents would have stepped in and put an end to it. I always had to ask to turn the tv on, which worked out pretty well.
Okay, this is how much tv we are watching around here: Dh gets up with ds at around 6:30 - they play, eat some breakfast, etc. Dh sometimes watches Sportscenter with ds in the room for about 15-20 mins. Then at around 8:15, after dh is out of the shower, he lets ds watch Clifford while he gets me out of bed and dh gets dressed for work. Tv goes off. Then around 8:45 or so, ds and I usually turn on Sesame Street. For most of it he just plays while watching, we sit together, or we go into the kitchen to make some oatmeal, etc. There are certain segments (like Journey to Ernie) that he just sits and stares at. Sesame Street ends at 9:30. Then I get in the shower, with ds in the bathroom with me. Then, I try to get dressed and put makeup on. If ds is letting me do this, then the tv stays off. But if I'm trying to get out of the house and ds just won't let me have a moment, then I guiltily turn on the Teletubbies for about 10 minutes (it ends at 10). And that's it for ds's tv. In the evening the tv is sometimes on, but usually not until ds is in bed.
We only let ds watch PBS, cuz dh and I both hate commercials. And if we're watching regular tv, we always mute the commercials.
Ds is 18 months, and we just started watching these shows about 2 months ago. I already feel like it is a little too much, but then I am pretty paranoid about too much tv. I just feel like it's already going on almost 1.5-2 hours a day, and he's not even 2 yet. But he is playing, walking around, and sometimes not even paying attention for at least 1/2 of it. He has one So Smart video that he watches about 1x a week. He used to absolutely love it, but it's lost some of it's appeal.
Anyway, that's what's going on over here.