The Web Design Field Manual (http://webfieldmanual.com) might well be the only bookmark you will ever need as a web developer. Ok, maybe not the only bookmark, but certainly a very useful one.
The Web Design Field Manual contains links to useful tools and inspirational sites. The site is divided into eight sections including: Inspiration, Style Guides, Process, Workflow, Toolbox, Grids and Typography, Best Practices and Accessibility.
About the only thing missing is a general section for links to sites like A List Apart (http://alistapart.com), Smashing Magazine (http://www.smashingmagazine.com), Noupe (http://www.noupe.com) and Web Designer Depot (http://www.webdesignerdepot.com).