Thank you so much for all your replies....I have been feeling like a horrible mother the past few days for sure. I have felt defeated by my DS4 AND by myself for not being able to manage the discipline.

It is in the past 2 weeks DS4's behavior has become more defiant. I want to say that he is the "perfect" kid in school (according to the teacher), very mellow and kind. So I guess he has to take it out on us at home right....;-) Also, clarifying the yelling. When I say there has been yelling I don't mean actual screaming, but more like an angry, louder tone of voice. I hate hearing myself talking to him angrily though. And I know he does not respond to it very well so it is a negative all around.

You are right about nipping it in the bud AS SOON as he starts up something. What has really been the issue is the constant ignoring/saying no to everything I ask him to do. Here is an example of a conversation:

Can you come and get dressed now please?
I will when I am done with this?
OK, finish writing that one line and then come please.
No, I am going to write the whole page and THEN I will come.
No, you need to come now. (By now done with the one line)
No, I am not! YOU go and get dressed! I am NOT coming!

The only way to get his to come in a situation like this is to do the counting to 3. I don't want to use that technique multiple times/day though in fear that it will stop working.

Then of course there are times when he just flat out gets angry about something and he runs up and tries to hit. This is when I immediately take him to the time out spot, where he WILL stay put.

We do take away watching videos on YouTube at night if he doesn't act right. But it is usually an all or nothing deal. It is not taken away in increments.

My plan is to do it Super nanny style for the more serious offenses. The question is what to do with the not AS serious, not listening incidents...