I'm a bit biased because I build websites,... but just ask ppl I've built sites for, I've yet to hear anyone saying that they don't get work from it!
I think most ppl on here who say their website doesn't bring in work are ppl who haven't had their site optimised properly for Google. Do it right and get on page 1 for all your keywords and you'll defo get work from it.
I'm actually just building a website for my new "Web design" company. I find it the perfect compliment to window cleaning,.. something that can be done regardless of the weather, and even in front of the TV on dark winter evenings!