The chart below from ICP clearly shows that in 2011 the U.S, Japan and most of Europe have the highest living standards in the world by some margin. Economic size is far from everything.
For instance, China has 1.3bn people compared with the 300m or so in the US, yet living standards in the U.S, Japan and most of Europe still far exceed those in China and India put together.
The chart from the ICP report shows this fact using Real GDP Per Capita against the Cumulative share of global population.
Source: International Comparison Programme (or ICP) is a loose coalition of the world’s leading statistical agencies, hosted by the World Bank in Washington.