Do you need to have a slick site to show off your work. Not necessarily. But done correctly, it could help you stand out.
If you're putting together your book online, here is an article from Smashing Magazine you may find interesting.
I do not agree with everything in this article. And I don't think every examples of great sites on their list is worth highlighting. Still, it's worth sifting through to get a sense of what you want and what you want to avoid.