Hiring a web designer is difficult. Hiring a good one is down right near impossible. What exactly is a good "web designer"? A lot of companies incorrectly lump several very different roles together and pin it on the "web guy/gal". What kind of work do you expect this "web person" to do?

redesign the web site/web application's look and feel
make the web application accessible on PDAs and cellphones
make a new set of icons
design the printed brochure for the trade shows
...etc...

The main problem is, some of these are tasks for an artist -- a visual artist while some are for a programmer, and some are for an information architect. Designing a logo, or a set of icons, are (mostly) a art, creative task. Analysing a web application's content and fit it into a CSS driven site is a task for an informatio architect. Implementing a good set of CSS I say is a task for a programmer-type analytical person. Can a person be good at all three? Unlikely.

The industrial trend is then to lean towards the self-taught artist who learned CSS on her own. Artistics people sometimes make good programmer because they should be creative, and appreciate of beauty, hence elegance. This is still a compromise. I believe a company should hire two different person. First is what I called a "User Interface Architect" that is fully aware of current web presentation technology (CSS, DOM) and whose job is analysis/design/implement of web interface. She should NOT be insulted when the graphics jobs is given to a separate "Graphics Artist" whose job is to "draw" and give the company's output (application, print, office, etc) style. If you cannot afford a good artist (I thought artists don't make too much money !!? ) outsource that function.