My personal vote, after about three million years in the industry: stick to Structured languages while time is limited. Learn everything else if and when you must.
This means:
C/C++: highest paying jobs
C#: most ubiquitous jobs
Java: most portable code (and includes Android)
JavaScript
: 99% solution for web-based scripting
The language structure is so similar, all four languages can be learned (without deep Library knowledge) fairly quickly and easily, leaving you able to work with drivers, games, business apps, web pages, mobile apps and just about anything else.
When and if you find the need to know
VB.Net, you can tout your overall programming experience and "extensive knowledge of the .NET framework from using C#," and still be a strong candidate for any job.
Cheers!
Scott