Feral wrote a piece with some of the tech he was looking at for when he finally gets off-grid. And some of those things linked to were just awesome. Worm farms would be a great way to keep yourself from having to be in contact with the outside world because eventually you will need that septic tank cleaned out, but not so with the maintenance free worm farm.
So here are a couple of my thoughts on the matter.
Energy consumption will perhaps be the biggest factor in going off-grid. How you generate power will depend greatly upon your area with wind being a huge one in my area. But there is a very interesting tech being deployed in Israel which is a solar panel that looks much like a satellite dish where the dish is mirrored and point to a single collector. This is much more efficient than the standard panels and the investors had plans to bring it to the US before long. I apologize for the lack of links on that. I came across is on WND some time ago but cannot find a link. Another thing that Israelis do is passive solar water heaters. They estimate that this saves some 2,000 kWh per year. For more savings on heating water, look to tankless solutions. The only downside to them is that you might never get your teen out of the shower.
As for the home itself I think two things really should be considered if you are putting up a new building. Solarcrete is a very impressive technique for building which they claim will save 60-100% of heating and cooling costs versus traditional methods. And with an R-36 rating, its not hard to see why. A potential drawback is that these structures have no air transfer (other than windows of course) and so they specifically recommend not using gas to provide the heat for a home. I would think that applies to fireplaces as well? Other building styles are discussed in detail here. This site just might give you what you are looking for in building techniques. I personally also like the idea of an underground/buried home. This way the earth is sheltering and insulating your home. Here is another link you might find helpful.
With housing more or less covered, this brings us to food. I don't have links for greenhouses, but I do regularly drive by a house that now has two very large homebuilt greenhouses that utilize what look like aluminum fence poles and thick plastic sheeting. They recently put up the second one so I assume that the first worked out well enough for them that it was worth the cost. I don't know how they work out venting as I don't see any vents on it. Another idea I have seen is to partially bury the greenhouse. This provides insulation from winter weather but doesn't much cut off the light. All it would take is a couple feet, probably no more than three depending on how you set up the plants. Another interesting way I just heard about is someone who uses hydroponics and at the bottom is a fish tank that he keeps trout in. This way all the water flows down to the trout, the waste from the fish gets put back into the plants and fish are readily available at the same time. That way there wouldn't be any waste in the system at all.
Food storage? Underground. (I am sensing a theme here...) Its how our forefathers did it and it still works very well today. An underground pantry can keep everything cool in the summer which would greatly reduce the costs of keeping foods fresh. One could even keep a freezer down there and as the temp already stays low naturally that should reduce the amount of energy needed to maintain freezing temperatures.
So thats the end of the big stuff, here are some of the little things that can be done now. Still on the food storage bit, remember that a full fridge/freezer uses less energy than an empty one. This is because of air transfers. If ya can't fill it with food, consider bubblewrap. It will fill the space and prevent the cold air from escaping when your little ones stand there looking for something.
Energy needed to cook can be reduced by steaming vegetables instead of covering them with water. Its also quicker and healthier. Also consider using a pressure cooker. Depending on what is being cooked, they can even be faster than the microwave and no doubt use less energy in doing so.
I use, and LOVE, my blackout curtains. They block that annoying ball of fire that tries to get me up early on the weekends and they have an added benefit of greatly insulating the biggest energy hole in your house: your windows. I have also found that I can keep the windows open but those drawn and I will still get the fresh air in the house but avoid the direct sunlight that overheats the house in the summer. I would also one day like to replace the standard plastic hanging whatevers that everyone has on their sliding glass doors. No efficiency at all in those and not exactly good looking either. I figure it would cost less than 150 at wally world to get a set of nice curtains and the cheaper fancy double rods with valance.
Oh yeah, one last thing. TVs suck energy even when "off." In fact, anything that can be turned on by a remote sucks energy at all times. Use a power strip to cut off the power to them when not in use.