I always find the topic of children vs TV as an odd dichotomy. It's like everyone watches tv but nobody wants their kids to watch tv. I'm not saying anyone posting in this thread is a hypocrite, not by any stretch, I'm making an aged observation.
Since I'm picking up a level of fear here in the question "Is TV harmful at all to my infant's development?", allow me to dispense a dose of realism: All things in moderation. An apple a day won't kill you, 20 apples a day might. A beer a day won't kill you, a case of beer a day might.
Your baby turning her head to look at the tv while you watch a movie is not going to irrevocably poison her mind.
For an infant or toddler, hanging out while you watch Dexter or Game of Thrones isn't going to matter. Dare I say popping on Baby Einstein or Blues Clues for an hour or whatever while you make lunch or pick up toys could actually be positive because you know where they are while your attention is elsewhere, which beats the alternative of NOT knowing what they could be getting into while you're in the basement switching out the laundry.
That's the 'apple a day' part that won't hurt. The 20 apples a day part is parking said child in front of the tv all day while you play facebook games or World of Warcraft. (Yes I've known people like this)
Bottom line: the television is a single tool. It has a place in the rearing of your child just like books, music, walks in the park and playing with megablocks . . . 10 solid hours of any activity will be no good. As the parent, make the decision as to what you think is too much and be ok with that, because the fact that you're here asking immediately puts you above the type of parent that you don't want to be.
(Dexter and Game of Thrones were chosen for comedic effect and they're 2ndary to the actual point. Please don't chastise me about feeding violence and sex to a baby)
[next day edit]
I keep coming back to the apparent fear in the phrasing of the core question
"Is TV harmful at all?"
while I gave my opinionated answer to the direct question, the answer to this question is "If it was, we'd all be idiots."
I may have read you wrong here, but it's ok to lighten up a bit. A healthy level of concern is great, it's a clear internal check and balance. You're doing what you can to ensure your kid grows up healthy, wealthy and wise. But it can be overdone, and it usually happens with new parents that keep looking for the "how to raise your kid" book and panic when they can't find it. (Note: it doesn't exist.)
I personally have known parents take all the labels and techniques and 'fad family advice' too far. One couple I've known for a while wound up raising weird kids. They wondered out loud to me why their 13 was weird. But didn't want to listen to me when I told them it was the wheat germ brownies (or whatever it was) and the other arbitrary decisions (like "no tv at all till they're 4yo") that drowned out their inner parenting voice. A grand total of 20 Cheesey Poofs from a couple lunches in a week isn't going to kill a hi-chair toddler. And lets face it. . . cheesey poofs are fun to eat.
Listen to that parenting voice. You can read and research, and asking on these boards is great, but ultimately you're President of your child. You get to take in all the info and then do the thing that you feel is best (not RIGHT) and be confident that it is what is best for your child. you know your child better than anyone. If you act in their best interest, you'll never have anything to regret.
Yet, the closest family member who will see your girl a grand total of 50 hours in a calendar year will still try to tell you what to do and chide you for doing the "wrong" thing. Their opinion should go into the pool with all the other info. Just Smile -n- nod and then stick to your own goals. All things being equal, everything will turn out just fine.