Mark has it right. The best bang per the buck is the air sealing & insulation, windows, and the analysis to make it a truly passive self-heating design, with very low peak & average heating loads. The only good off-grid home is the one that uses electricity only for essentials, not big energy uses like space heating.
With all of the extra PV and batteries required to run the pumps. The lifecycle per-kwh cost of the batteries alone
is on the order of 50 cents/kwh, and the more you need power to make stuff work the more battery, inverter & PV you need.
If optimize the insulation, passive gain, and thermal mass of the house to where your heat loads are under 20,000BTU/hr even on the darkest coldest nights you can heat with a small EPA-rate woodstove that NEEDS no PV, pumps or batteries, and you can size your PV to run the essentials (like a small refrigerators and some lights, and maybe your notebook computer with the internet link, etc.) And you can size the solar thermal for your hot water needs.
There has been no recent performance breakthroughs on solar thermal. In most instance flat panels are the better bang/buck- evacuated tubes make sense when you have a very high delta-T between the working fluid and the outdoor ambient. If you're moving to 10,000' in the Sierra it may be worth it to gain some mid-winter performance, but in Oroville you'll get more performance per dollar out of flat panels.
There have been major price/performance improvements on PV in the last 5 years, but alas, not so much for the storage batteries & inverters, which will be more than half the upfront cost of the system. Buck-a-watt panels abound, but at the very low end price fringe not all vendors stand up, using sub-standard LCA and flimsy mechanical components. But it's a moving target- volume pricing on first-quality PV will hit 50 cents/watt in under 5 years, as better kerfless thin-silicon mono & poly crystaline panels hits full production stride. But the price of lead-acid batteries and charge controllers/inverters aren't on a similar falling price trajectory.
Grid tied inverters are coming down in price though, and sub-$2/watt all-in pricing (installed) isn't far away. (It's already there in Germany, and is expected to hit that in the hotter TX markets next year, taking advantage of some newer lower-cost lower-labor panel racking technology coming out of India, released to production just this year.)
BeOpt is a pretty good energy use download freebie (courtesy of the US D.O.E.). The PassiveHouse US (PHIUS)
spreadsheet tools work too, and are pretty cheap. There's a learning curve, and garbage-in==garbage-out with a lot of these things, but it's better to spend the time now than the money later, if the whole thing is going to be DIY. This is a well-trodden path- there is a lot of information out there, but finding the optimal bang/buck requires actually using it, not just comparing performance specs between different types of solar thermal, none of which are truly appropriate. Get the load down to next-to-nothing first, and the size & cost of what it takes to handle the load become affordable. High performance building envelopes aren't very sexy technology (and rarely subsidized) but it's the necessary first-step for off-grid.