I really disagree with Brandon. Some people's situation won't accommodate solar, but the idea that you have to nix out your power bills within a few years for it to be worth it...is going to look very quaint in a few years when solar panels may not be available or affordable--unless you live in China, maybe--and the grid may be going down more often, grid power may be climbing rapidly in price...whereas panels are quite cheap now. The whole system, especially if you go off-grid, is not so cheap, especially if you have to pay expert installers and red tape fees, but could well be worth it.
We installed 4 panels in 2009; my husband is an electronics experts, so he did it all himself and since it's off-grid, there was no need to pay anyone or to argue with an electric company or government person. That system had eight golf-cart-type batteries, and the total cost was $9070. The capacity was 880 watts. At that time both the US and my state of West Virginia had 30% tax rebates for solar, which cut our costs in half. Those batteries are good for 5 to 7 years--we replaced them in the seventh year with some tubular lead-acid batteries that should still have 80% of initial capacity in 20 years, $4000. We also added two new panels. The first four in 2009 cost $600 each and were 220 watts; the ones maybe eight years later were virtually the same dimensions, 315 watts each plus more efficient in low light conditions, and cost $200 each.
Around here the grid goes down pretty much every year, usually for a few hours but sometimes it's a week in a widespread outage. Our system went partially down once in 17 years; fortunately it was the first year when the inverter was still under warranty. A lightning strike damaged it via the AC system. The company replaced the relevant part of the inverter free, and we set up a system where we turn off the AC switches except for the refrigerator when it's stormy or potentially so, and if a hellacious thunderstorm is raging around, we turn off the fridge one too. Last year my husband did a test and could not detect any efficiency loss. The idea that panels are only good for 20 to 30 years is false.
The key is that you do NOT need to power your house at typical first-world levels of indulgence and waste. Before sizing your system, figure out how to minimize power use. We use about 2 kilowatt-hours a day, barely 10% of what is typical in the US, and have two laptops, a refrigerator, blender, toaster and microwave, power tools and vacuum cleaner, and a well pump. Most of those things we use occasionally; some we use only when the sun is shining (because there is efficiency loss when power goes into the batteries and then comes out.
Incidentally, our panels are not on our roof. We built the house next to tall trees on the west side, so we are in total shade from noon on in summer--hence we don't need AC and don't even use box fans except for winnowing grain. For cooling we have several tiny fans made of a pair of desktop computer fans soldered together--these use like 5 watts, and there is one next to where I read, one upstairs when my husband sits at his computer, and one over the bed for those few hot nights. But this means the house roof is not ideal for panels, so they're on a yard mount my husband designed (details at spectrumz.com/going solar). 60 feet from the house. So no need to make holes in the roof, changing the angle of the panels seasonally is quick and easy, and scrubbing snow off the panels sometimes more than once a day--when we need the watts the most--does not require walking on an icy roof or hanging out a window when it's 12 degrees.