Links
http://users.nac.net/falken/annoying
This site may be a bit dated, but it's still a useful resource on how simple HTML mistakes, as well as misuse and overuse of certain features, make for a duly annoying experience for your customers.
YouTube
Hey, everyone else links to YouTube (and oftentimes not just a specific movie on YouTube, but just the front page) so why can't I?
ToastyTech.com
If you're into NSFW rants about Windows and Microsoft, check this site out. (It is also the home of a nifty "GUI Gallery", which shows all kinds of WIMP (WIndow-Mouse-Pointer) interfaces from many different operating systems over the years.)