Elinux is a comprehensive Wiki covering Embedded Linux in general, with a large corner dedicated to our beloved Raspberry Pi.
Adafruit sells lots of nice gadgets for the Raspberry Pi. But they've also got quite some interesting projects and lots of things to learn on their pages.
Jan, a.k.a. the fun smurf, is a very experienced Debian user who writes about his Raspberry Pi adventures on his web log.
Nice projects for your Raspberry Pi, including surveillance camera and temperature and humidity sensors.
A site with lots of interesting Do It Yourself projects running on a Raspberry Pi, an Arduino, or even on a good old Z80 processor. They are previously known as www.diyhacking.com.
If you think your Raspberry Pi related Web Pages or Blog deserves a place in this hall of fame drop me an email and I'll see what I can do for you.