Another less commonly discussed option is community solar (also called offsite solar). It's especially attractive if the roof line of your house isn't ideal for solar panels or if you expect to be replacing your roof within the lifespan of your panels. (Or if you have a historic association like I do that makes almost every home project impossible.)

You still purchase and own the panels, but often a third party maintains them for you and they are installed as part of a large, offsite array. Since they're usually installed at ground level, they can also do more interesting things like follow the sun. The way it works is the power your panels produce is subtracted from your energy usage via an arrangement made with your utility provider.

Like any solar purchase, the cost of your panels can be financed over time and charged against your energy production. So the net effect is your power bill just goes down until the panels are paid for. At that point all the power you generate is deducted from your power bill. To me, it's most all the upside of owning panels on my roof.