* Have a co-founder (or founders)

* Have some ideas

* Have some savings (I quit with above 1 year or rent)

* Have equipment, backup drive, laptop, and ec2 (servers)

* Setup some ways to quickly get moving Wiki, Blog, Github, Ticking System

* Have a layer to help you incorporate and deal with anything that comes up.

We quit having a few ideas and not knowing which we would start with. I guess if you aren't in a rush I wouldn't quit until you had the idea you really wanted to start working on.