I have solar panels - I had them installed a year ago.
I had been thinking about it for a long time. It was when I discovered that IKEA had a special deal that I decided to have them installed. My prime motivation was to reduce my dependency on fossil fuels - I wasn't greatly bothered about about making any financial killing. That said, I am pleased to receive a small cash present every three months - and my electricity bills now show a significant reduction.
One point worth considering is that the capital cost of solar panels has plummeted. My installation cost a little over £3000 - over 5 years ago it would have been at least £10000.
Similarly had them installed just under a year ago after considering it for some time. So far really pleased - both electricity and gas bills are down (the latter as we have a device that diverts generated electricity into a immersion heater if we aren't using it). Then we also get a nice feed in tariff payment every so often.
And contrary to some of the reports our generation is significantly ahead of the predicted levels - so we've generated our estimated annual amount in less than 10 months. Should pay off in 8 years or thereabouts.
Plus of course there is the 'feel good' factor of generating electricity in eco-friendly manner.