I pick up back issues of Communication Arts (Ebay), as well as look on their web site (www.commarts.com) for their web site of the week.
Sometimes I go to Elance and browse portfolios and occasionally find some interesting "Corporate" looks there. But generally, I ask my client what web sites do THEY like, and WHY they like it then design something along that style (if it's appropriate for them).
There's a great book out called "Fresh Styles for Web Designers" that has some neat and work in it, as well as explanations. What I liked was the author's manner of Categorizing styles in ways one may not have thought of before. Good reading, at least for me.