How Much Is Enough For Early Retirement?

A little while ago Len (from Financial Farmers – go check them out) commented on my post How We Made Our First Million Accidentally. He asked about financial freedom, not having to work, and early retirement. In my reply I talked about maintaining principal, inflation and a bunch of variables. We both had similar goals (although 40 seems a little to soon for me), but had very different capital requirements ($3+ million vs $1.25 million). So I wanted to redo some of my calculations, and was also questioning some of my assumptions. Needless to say, I jumped straight to Excel and put in...