I'm currently building a house for myself. I'm going ground source heat pump for my heating. Personally I think solar is a waste of time. With the government grant, I worked out that a solar system would give me 1 free month of electricity per year. Not worth the outlay as far as I'm concerned. Now the grant is reduced, it's definitely not worth it. I'd rather put the £12k towards new toys!!
If you have mains gas, that is still the cheapest way to heat your home, however, if you are off mains, I believe that ground source heat pumps are the way forward.
Thats my penny's worth!
Chris
PS. Hoping to go flying over Cheshire tomorrow, weather dependant.