At the point you have a long list of projects (pebbles) and are trying to decide on where to begin...

AFTER YOU HAVE SUFFICIENT INCOME (where you don't have to worry about paying the bills!)...we reverse the old way of ranking projects (which was 1. Money  2. Network  3. Passion)...

The PebbleStorm way of ranking projects:

1) Passion

How interesting / fun / enjoyable would it be?   Which one(s) are you most drawn to?

2) Network effect / leverage / scalability

Would it benefit the network?  Give you more leverage or scalability?  (A software product)  Would it accelerate the other pebbles you're working on?  (A book or blog, for example, starting a conference...)

3) Dollar opportunity

How much $ could it generate?

A core value in PebbleStorm is that you should be doing what you love to do most of the time!  You don't need to sell yourself short by doing things for the primary purpose of making money, because over the long run, you'll actually make less! (And be more stressed)  By focusing first on your passions and talents, the quality of your output and passion will go up.  It's easy to produce great work when you love it :)  

Furthermore, it's virtually impossible to predict where opportunity(s) will go and which will end up making you the most money (over a long period of time)...so by focusing on your passions, you

1) will enjoy the ride no matter what, and

2) will increase the chances that you'll make even more $, because you'll be the best at whatever it is you're doing, and will become a magnet for others seeking that passion in their own projects.