There are many different kinds of solar roofing systems out in the market. They serve whether to heat your water or to obtain electricity. They also come in various sizes and types: from traditional roof tiles to more modern slates.
They not only help you in reducing your energy bills but also allow you to be more independant and off-grid, an advantege if you live in very remote zones where the energy networks are bit difficult to reach.
And I prefer them to solar panels because you can easily integrate them to your roofing system and they will be no more different than your surrounding roof tops.
They certainly will not look like monster add-ons to your roof!
Here a few examples (videos only):
GLASS ROOF TILES
SOLAR TILES AND SLATES
SOLAR TILES Design For the Future