I recently heard a radio interview with Jill Conner Browne, the author of the "Sweet Potato Queens" books. She's really runny and witty, just yesterday I pick up one of her books. On the radio interview, she said one thing that really stuck with me: "Do what makes your heart sing, and the money will follow".
I quit my job the next day...
I now design fountains for a living, and bought a small (tiny, really) company that makes electronic controllers for fountains. I couldn't be happier, now if only the money will follow...
Best of luck to you!
Larry