Here's a few recent buys:

  - Javascript: The Good Parts (http://oreilly.com/catalog/9780596517748/)
  - High Performance Javascript (http://oreilly.com/catalog/9780596802806/)

It's always a good time to buy a few classics:

  - Information Architecture for the WWW (http://oreilly.com/catalog/9780596527341/)
  - Javascript: The definitive guide (http://oreilly.com/catalog/9780596101992/)
  - Beautiful Code (http://oreilly.com/catalog/9780596510046/)