Books...

I've finished Krug's Don't Make Me Think and Garrett's The Elements of User Experience and still have the other two to finish. The best thing about each book is not that either teaches you anything completely new, but more that they help you to clarify the knowledge that you already have from an information architecture and guerilla usability perspective.

Personally, I've found the fact that both books sent me back to basics of more value than anything new I could have learned. Common sense is often (but not absolutely always) such a valuable commodity