When we say that efficiency is crucial for a green future, we mean it. Look at these graphs from the Lawrence Livermore National Laboratory (they are similar to those used by Amory Lovins in his book Natural Capitalism and in his Winning the Oil Endgame video presentation). They show that out of the ~97 quads (1 quad = 10^15 British thermal units) or ~103 exajoules (1 exajoule = 10^18 joules) generated from various sources in the US in 2002 (nuclear, hydro, biomass, natural gas, coal, petroleum), 56.2 quads or 59.3 exajoules were wasted, lost, unused for any valuable work. That's more than half. We all need to take a moment and seriously think about that.The ratios for U.S. Energy Trends were pretty similar in 2001, 2000, 1999, 1998, etc. It's not a recent trend.
For those who think that radically increasing efficiency (in energy and materials) is a pipe dream and that we're already doing what we can do, we suggest having a look at the aforementioned Natural Capitalism, the Rocky Mountain Institute's publications on energy, the Factor 4 - Doubling Wealth, Halving Resource Use book (a bit older, but still relevant) and the Factor 10 Institute.
There is also a very recent study titled [R]evolution (pdf) by the European Renewable Energy Council (EREC) and Greenpeace International which concludes that "half of the world's energy needs in 2050 could be met by renewables and improved efficiency". It highlights different scenarios for different parts of the world, with a different mix of renewable energy sources depending on what would work best (more wind in Northern Europe and North-America, more solar in the Middle-East, etc), but a past of cheap energy, bad design (or at least not energy-efficient design) and inertia mean that big efficiency gains can be made everywhere.
Political will is another big element. Unlike what some people seem to believe, political will doesn't just come out of nowhere. The public needs to demand these changes (that's already observable: in countries where the population has a higher level of eco-awareness, the politicians don't have a choice but to propose green measure, but where the level of eco-awareness is low, the politicians can more easily ignore pressing environmental issues without paying a political price).
So educate yourself, spread the word and demand change.