With that said, though, we'd definitely welcome specific feedback (search results that don't look right, etc.); I know that sort of thing can't be mentioned here, so feel free to post that on our Webmaster Help forum, which we Googlers monitor regularly.
I recall GoogleGuy and/or Matt telling us to report such poor or irrelevant search results through the "Dissatisfied? Help us improve" link. Have you changed recently that "recommendation" to reporting on your Webmaster Help forum instead?