M.R.
You are like millions of other people in this economy. It is hard. There is no nice way of saying it. We all live the lifestyle our income allows. Very few of us have half our money going into savings/ methods we can easily give up, so there is no question that cutting your lifestyle in half, even for a little while, is going to be hard.
I read through your list and I heard all your reasons for NOT wanting to get rid of things/NOT being able to give things up. No one here is going to be able to look at your budget and say the best thing for you. Or that one or the other is an irresponsible choice. You weren't buying diamonds and luxury items you were providing a nice life for your children. And although the income wont be there for the $ things, you will be there for them (it isn't an all bad thing happening).
You and your husband are going to have to really sit and think about what matters. Somethings will have to go, but your guys are taking the mature proactive step in setting a budget and trying to chose what you lose, instead of letting life chose for you. People here can say 'oh for me the grocery bill is the first place I would cut', or maybe the car or maybe the security of knowing you have affordable quality childcare when you do go back to you current income level.... but ultimately we are all speculating. You don't have to give up everything, I bet the house and the student loans are 2 things on the can not give up list.
It is good to get ideas of how to save a dollar here and there with food and cleaning products or energy bills, but ultimately you guys dont need to cut a dollar here and there; you guys need to cut major expenses and then dollars here and there to fit it all in. Create a list and number the things in the order of importance. You will have to chose which lifestyle habits you want the most/you can't change. The tuition for the kids, your student loan contract, ect and number them. After you have numbered everything then go down the list and where the money runs out look and see what you would lose, if it is all groceries then maybe re-evaluate the list as you need some food to keep the kids alive. But after doing that until your are sick of the list you will see the most important things will remain.
Good luck! I am sure plenty of families here would love to hear what you did do. You aren't alone too many families in this economy are faced with the same impossible decisions and would love your support of hearing how you made it/are making it.