Pies are great to show relative sizes of surfaces, better than bars or columns. When it comes to comparing breakdowns on multiple dimensions though, the column chart cannot be beaten. See this example taken out of Haaretz this morning. What did I fix:
  1. Two columns instead of two pies
  2. Get rid of the 3D effects (earlier post)
  3. Use consistent coloring for data series
  4. Use consistent ordering for data series
  5. First the chart with the number of households, then the chart with the breakdown of income