Where we need to be
We need to eventually get as close as possible to a world without smokestacks. Where there are now coal and natural gas plants will eventually need to be wind farms and solar power plants. This is by no means going to happen overnight, but is the goal we must be striving for. Imagine a world where homes are heated and computers powered and goods made without the massive amounts of pollution we have today. We will need to rely on a mixture of different technologies that use less and less on fossil fuels until we are at a truly clean energy economy. Electricity will come from wind, solar, nuclear, and a couple of other technologies we talk about in the emerging technology section. We need to get to the point where we have stopped pulling resources out of the ground and burning them, adding their carbon into the atmosphere where we can't really do much to get it out yet.
We will need to rely on a mixture of different technologies
We need to not only use clean energy technologies, but we also need to have a smarter electrical grid energy storage. The grid needs to improve from the 19th century technology we currently use and get smart enough to handle changing energy supplies and demands. There may need to be some real time pricing and the ability for the grid to connect with smart appliances and electric cars and communication with home and business owners about the energy they are using. There will also need to be ways to store energy so that we can make energy at the times when its most convenient and store it until it is needed.
Each technology discussed here has its upsides and downsides, which is part of the reason we use so many of them. The best thing we can do is to reduce our consumption, which you can learn more about in the Using Energy
link. Even the best wind turbine isn't better than the one you didn't have to build.