How about learning to sell? I believe being able to sell a technology or product will be an invaluable tool that will carry you for the rest of your career, no matter your chosen field. Having a technical background gives you a step ahead as far as selling technical products/technologies.
If you are talking about specific technologies that are important, I would consider:
1.) Web services. New specifications are on the horizon therefore there are very few "experts" in web services.
2.) Pervasive applications. J2ME, Bluetooth, RFID, etc etc.
3.) Grid/Autonomic.
4.) Stable vendor products. Websphere, SAP, Peoplesoft, Oracle, DB2, etc etc
I'm not sure if breaking into Nanotechnology is as easy as learning
Java.