The product will reflect your passion.
This is always the holy grail of mISVers.
Doing something you love and make money out of it.
I would even stoop to say that the consumer market will tolerate ads in desktop software if it serves their purpose and is freely distributed -- this means you've come full circle back to B2B, selling ads... The secure $$ is B2B (dangit).
I forgot this possibility, the sky is the limit in this area.
I love the community!