Some sites are useful, some sites are beautiful, some sites are cool. Some are all three.
Technology resources
Slashdot An extremely ugly interface but a valuable resource on anything to do with technology.
Mozilla Home of Firefox and Thunderbird, alternatives to Internet Explorer and Outlook that I would not want to be without.
World Wide Web Consortium The home of standards on the web, the W3C site is a must for anyone working with the web.
CSS resources
CSS Zen Garden Possibly my favourite site at the moment, this website demonstrates the brilliance of good CSS design and looks amazing. It's a simple concept: one HTML file, over a hundred different designs through the wonder of CSS. The guys behind it even have a book out.
css/edge Eric Meyer's demonstration website showcasing some of the effects that good CSS can produce. Sadly, it also points out how bad Internet Explorer's support for CSS is.
A List Apart Although I use this site primarily for CSS tutorials, it has articles on many other subjects. It champions good, clean, accessible code and gives you the building blocks for good designs.
Blogs
meyerweb.com Eric Meyer is one of the leading authorities on CSS.
mezzoblue Dave Shea, one of the guys behind CSS Zen Garden, discusses anything to do with the web.
A Writer's Life Lee Goldberg, TV writer and novelist, writes about writing.
Elizabeth Bear Discusses writing and provides insightful reports on progress and problems.
Whatever John Scalzi is a writer who discusses writing and the publishing world.
Reading material
.net The first Internet-related magazine that I picked up and still a monthly must. There are always interesting articles on web design and general Internet issues and the Web Builder section has provided more than a few handy hints over the years.
Web Designer Specifically geared to web designers, it's filled with useful tutorials, profiles and articles. Shame the website has so little information.
Digit Magazine This one was discovered a couple of months ago and stands out because it is about all digital creativity, not just web design. The website is also good, with lots of reviews and news from the digital design world. There is even an RSS feed, something that I have learned to love since installing Thunderbird.
Other resources
morgueFile Not as gruesome as it sounds - this actually a great resource for good quality stock photos. The amazing part is that they're free.