The math I did showed I could use it (The 200 watt and 200 amp-hour system) to run an Edgestar at 40 degrees farenheit for about 2 days. (It draws about 1200 watt-hours per day under normal conditions in the summer.) And that it would take about 12 hours of direct sunlight to fully recharge the batteries. So, assuming I can get 12 hours of sun every two days, I'm good.
Obviously, that would be cutting it close in the winter, but it's also not very hard to keep food cold in the winter. Most of the time, I will be using it to run my home network, desktop computer, and any HAM stuff I have in the house. That draws about 1,000 watt-hours per day. If we don't get a lot of sun for a couple days, I can always just plug in the battery charger at night.
I will also be building one of these for someone who wants to use it to run a fridge for camping trips where he won't always have the option of running stuff off his alternator. I figured that 200 amp-hours and 200 watts would be the minimum to guarantee that the system will keep his beer cold about 95% of the time.
Of course, all of this is pretty theoretical. We'll see what happens when the rubber meets the road.