To MBA, Or Not To MBA

I should add a little info here:

First HN post, long time lurker. It's been a sleepless night spent surfing on great sites like humbleMBA.com, trying to get things straight.

I just wanted to get some thoughts out, and I certainly wouldn't mind hearing some opinions as well.

What do you hope to get out of an MBA? Why do you think an MBA will help you succeed in a startup? How many successful companies do you know that were started by MBAs in the last decade? What is the opportunity cost of doing all this?