It would be awesome if the scope of this thread included more than just alternative energy topics and was about ecology, environmental issues, nature, and conservation more broadly. As far as the existing topic, I think it is generally undisputed by non-political activists that nuclear power is the only real, viable alternative to fossil fuels for base load power generation. Geothermal is great, but is only feasible in certain areas. Solar is awesome for residences and businesses, but large scale solar fields are cancerous. Wind is terrible all around. Dams are absolutely horrible for the environment, and are becoming less reliable for base load generation as patterns of precipitation change. Other technologies like fuel cells aren't mature enough yet, but are really interesting and should be further developed.
To me, an ideal future would see most power generation coming from nuclear, geothermal and solar (at the residential scale), Wind and hydro should more or less just be abandoned as failed experiments. Coal and natural gas should be maintained as backup systems.