Which book? How to choose?

I asked myself something yesterday when I was trying to decide which of the many possible story ideas I should commit to working on next. I'll share it with you in case you have some decision to make, to which this line of questioning may apply.

I essentially had three story ideas revolving in my mind as main contenders for The Next Novel; we'll call them A, B, and C. (As with many writers, my problem isn't coming up with ideas, it's choosing which of my many ideas to use at a given time.)...