A very similar question was posed a few days ago with some pretty interesting replies - http://news.ycombinator.com/item?id=1015079 http://news.ycombinator.com/

A very similar question was posed a few days ago with some pretty interesting replies - http://news.ycombinator.com/item?id=1015079 http://news.ycombinator.com/item?id=1015079