Here’s a neat project of Chris Coyier’s that I had forgot about: Quotes on Design.
Basically it displays a random design-related quote, and you can load more by pressing the AJAX-ified “Get Another!” button. You can submit ones you like, and search for ones you’ve seen before. (Perfect for when you’re writing a blog post and need to find that quote from that one designer…)
If you’re into books, there’s also Quotable Books, over at BookAdvice.net.