I hope we get good, cheap photovoltaics soon. In the meantime, here are some things we did over the last 30 years that really made a huge difference from a plain money point of view.

1981 Installed solar water heater
Hot water may be about half of your household energy use.
Cost, after tax credits, adjusted for inflation, $5,000. Saved $35,000 in electricity bills, for a total savings of $30,000. Would have had to earn $50,000 to pay that.
The freezing problem has been solved by encasing the heat-collecting pipes in evacuated glass tubes (thermos tubes), and if you live in a really cold climate, running an antifreeze solution in the heat-collecting pipes. Depending where you live, after tax credits, this is about $2,500 dollars, which is about half of what it was 30 years ago!
(Not to mention that it is ridiculous to have wars to pump oil to ship oil to burn oil to make electricity to make hot water when you can just get the hot water for free or at reduced cost.)

2004 Housing clearly in a bubble, energy crises clearly coming (didn't know about all the securitization of debt and funny business going on at the banks).
Goal: get expenses down as much as possible before it all blows up.

2005 Needed to replace 25-year-old roof
New, conventional roof estimated at $25,000.
Instead had elastomeric roof coating applied for $12,000. It is wonderful. The heat does not enter the house to begin with, so the house does not heat up during the day and the refrigerator does not work so hard. Reflects back into space a substantial fraction of our global warming footprint.
Also reflects heat back into your house if the outside is much colder than the inside.
For example, see
http://www.leakmaster.com/hawaiian-s...d-ceramic.html
It can be tinted and need not be white, but of course white is slightly more effective.
Many elastomeric roof coatings and paints are now available with titanium ceramic additives to reflect heat, but beware cheap versions.
http://www.hytechsales.com/

2008 In full panic mode; no one asks me "What the hell are you talking about?" anymore.

2008 Installed complete set of hurricane straps and drove in complete set of HurriQuake nails, effectively doubling resistance to quakes and hurricanes. Total for materials $200.
http://en.wikipedia.org/wiki/HurriQuake
Insurance company cut homeowners insurance by $50 a year.
Roof should now withstand 130 mph (210 kph) winds.

Had house painted with the above titanium ceramic additive for total of $5,000. Paint should last twice as long, saving $5,000 on the paint job that will be skipped.

Replaced many lights with energy efficient compact fluorescents for $50. The warm white floodlight ones in particular are absolutely terrific and really cheap. Read labels carefully; there are a lot of choices that don't apply to incandescent bulbs. Buy one and test it before you buy many.

Our electric bill is now $60 a month, whereas our neighbors' are in the $200 to $300 range. Since the roof should last a long time (with a touch up every 10 years or so for $2,000), we shouldn't have any major expenses over the next sure-to-be-tough decade.

So the original $5,000 investment in the solar water heater saved the $30,000 that paid the $12,000 for the elastomeric roof coating, the $200 for the hurricane straps and HurriQuake nails, the $5,000 paint job, and the $50 for the compact fluorescents (and leaves some for the photovoltaics when the prices drop by 50% to 80% over the next few years).

I realize this is in Hawaii, but the above applies to large areas of the southern US as well, and is still applicable to northern areas, just with longer payback times.

We can't control the economic crisis, but yes we can control expenses or even eliminate some of them!