Well according to me its an idea which has its shares of pro and cons just like everything in life.But i have often seen such relations don't work out more often than not.. There are many reasons why the idea is doomed. Firstly in a friend you tend to expect a lot ,even more than a lover beacuse she is the confidante of your life.She knows you inside out and at times that knowing each other so well leads to irritation.couples discover that they have nothing left to discover in each other and life starts becoming boring.After marriage we tend to set some preconceived notions into practice which can't be actually followed because we are friends.After marrying a close friend either the friendship has to die or the marriage has to end.There are no options available for both to co-exist simultaneously