I can't agree with this. First of all, there are other elements of building a successful project that can be just as rewarding and satisfying as making a buck.

I can't agree with this. First of all, there are other elements of building a successful project that can be just as rewarding and satisfying as making a buck. Perhaps, the project is some type of "resume builder" which helps you along your way to making the big payoff later on down in life. Secondly, you can never know if a project is going to pay off in the end anyway. So I say work on the project that you would enjoy the most, and you never know, it could be the big payoff. Take Craigslist (to cite an overused example). He never knew his email list would turn into a website and make him phenomenally rich!