For Pie Charts - Alternative do Donut Chart where initial view is a regular pie chart with general categories, e.g. Firefox, Chrome, Safare, MSIE, etc. Upon selecting a slice the chart "zooms in" to the next level down. So if once selected Firefox Slice, they get a new next level down pie chart which has Firefox 4, Firefox 3.6, Firefox 3.5, etc.

Should support N-Levels, based on data provided. Need Some way to zoom back out up one level.