While ASP.NET is not as popular these days, there is still a lot of websites out there that need to be maintained. I have recently updated 3 such sites to be mobile responsive.
C# seems to be the preferred compiled language these days. Without having any previous experience in C# I was able to update a C# website based on my knowledge of VB.NET & C++.
Cascading Style Sheets is always evolving. Some small tweakes here and a static site becomes mobile friendly.
HyperText Markup Language is always needed on the web, but is not always done well. We hand code it, and do it compact and efficient (in otherwords webpages load very fast).
Structured Query Language is a very powerful database system. Most of our websites use SQL to make them dynamic.
VB.Net is great for learning how to code. While it is not as popular today, there is still lots of legacy code out there that needs to be maintained. Personally, I like it because it is easy to read and debug.