I'm surprised Ben would recommend a paradigm shift after only one language and one year of study.
I would recommend C#. It's more respected in the computer industry than VB.NET. It relies on the same framework objects that you've learned through VB.NET, so it should be an easy transition. You'll also find that examples and samples are more often done in C# than VB.NET, so you'll have that advantage.
After C#, I see 3 or 4 directions that you could go:
- ASP.NET: this is the next "commercially viable" step, that is, it'll make it easier to find a job
- C/C++: this builds on your C# knowledge, but moves you away from the .NET Framework and into the powerful (and dangerous) world of pointers and topics like memory management (and leaks)
- Java: again, building on the C-like structures that you've learned in C#, but giving you a whole new framework to learn in order to cross platforms (i.e., Windows vs. Unix)
- Ben's advice: getting my Computer Science degree, I had the opportunity to study languages like Prolog and Lisp. Out in the "real world," I haven't had much need for it, but as Ben said, it's useful to be able to shift your brain out of "procedural" mode and look at a problem from a different perspective.
Which direction you choose really has more to do with what you want to do with your knowledge. Are you (just) looking to get a job? Are you interested in the inner workings of hardware, so maybe you'd want to write things like device drivers? Are you happy in the Windows world, or do you want to move to other platforms? Or are you looking to be more of an analyst or architect, where thinking outside of the box will get you over the hump?
Good luck!