This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
The only advice I have on this is what technology are you working with most? Or if you aren't working with any of them at the moment, which do you prefer to work with? Right now, I can say the hot technology is web services. With the explosion of Service Oriented Architecture (SOA) everyone will need web services work to be done. On the other hand, SOA has a demand for the supporting technologies such as EJB, and to a lesser extent, JSP/Servlets. It's all there though. It's a matter of personal choice, and the career path you wish to take.