Good Cop Bad Cop

Abby has developed this habit of saying no to me in this awful, bratty way. It to obnoxious for a variety of reasons, but it also defies the concept of "respect" that I am trying to teach her. My philosophy is that if she learns this concept in relation to her parents, herself, and her stuff, it will carry over onto other things in her world like her friends and what not. (I actually just saw that this is an article in Parents magazine this month).
Anyway, this morning when I told her to do something she gave me her "no" and I told her that if she did that again she was going to get all of her Easter candy taken away, along with her TV privileges and all the magnets on her responsibility chart. A bit extreme maybe, but I can handle this no more.
So we made it through the day with no problem, then after dinner she hit her sister. I told her to go to her room and she gave me her bratty, irritating little "no" and I promptly put her in her time out chair. She didn't object until I reminded her of all the things that she was getting taken away. She could have cared less about me taking the magnets off of her responsibility chart (once it is filled she gets either a "Barbie Hairdoer Head" or a scooter). Once upon a time this would have been a threat enough, but I think she is over it. She also didn't bat an eye at me telling her that she can't watch TV until Saturday (this is really a punishment for me since I use TV as a babysitter like all good moms do). She lost it, however, when I told her that the Easter candy was either going in the trash or to work with Tim.
Apparently the loss of her Rain-Blo bubble gum eggs was the punishment to end all punishments, and now I feel bad. Did she need to have all 3 things taken away? Probably not, but that was what I had said this morning so I need to stick to it, right? Right. But that doesn't make me feel better about it. And honestly I don't really think that this is going to stop her from acting like this tomorrow.
What really sucks is that I feel kind of responsible for her acting like this. I think she is looking for any kind of attention she can get, even if it is negative attention. It is not like she doesn't have my attention, but I think she is still feeling the burn of having a little sister. Or maybe I just need to play the fucking Littlest Pet Shop game with her one more time so that she knows I love her.
Where is her owners manual when I need it?