In this economy you have to do everything to keep your skills fresh and current so that employers find you a desirable hire. I really though the tips provided in 8 Ways to Recession-Proof Your Programming Career where spot on when this article came out last year. And now that the TechRepublic has released 10 kills developers will need in the next 5 years. I have decided to give you some of my favorite Wrox books that align very well to this TechRepublic article.
You can now find this list on Amazon.com under the same title, Recession Proof Your Programming Skills
Learn ASP.NET MVC
didn't think I would leave my book out, did you? ;)
Learn RIA & Web 2.0
I beleive all these books are a nessisty in helping you improve your career. You don't have to understand or know all of this technology, but you should at least have one of these books on your shelf.