Well, you can pretty much write off VB and ASP (classic). VB still sort of exists (for new development) in the form of VBA, but VB and ASP are legacy tech that are pretty much useless outside of the world of soul-sucking cubicle farms living on the remains of Windows XP. C++ is used where it's used, but that's a shrinking world, if skills-in-demand is what you're after. It's mostly a toolmakers' language now; it's neither small enough for embedded or RAD enough for production. PHP, while ubiquitous, is a crowded space mostly geared towards bending various CMSs to your will. And Java proper tends to be the province of "enterprise" development; none of the cool kids are doing much with the language, even if they're all over the JVM.
C# is a good language, sort of what Java should have been. And you can do both real desktop and real server with it. If you really want to learn something new, though, you might want to look at an alternative JVM language like Scala (a hybrid class/functional language), Clojure (a Lisp dialect) or one of the JVM JavaScripts. (JavaScript is an immensely powerful and expressive language once you figure out that it's not other languages; it has aspects of Scheme and Self wrapped in an unfortunately Java-like syntax, which means that just about everybody tries to make it behave like something it's not.) You can leverage the libraries you know using syntaxes and structures you don't know (or would only rarely use with the awkward implementations that vanilla Java provides). Node.js is good for overhauling your thinking - almost everything you do is "fire and forget" rather than "sit and wait" - but you'd need a *nix box (or VM) to play with. Python is nice if you stay away from Django. (Like any big framework, Django starts off by making things easy, but the moment you want to do things differently, it's a fight for every inch of territory. Flask will have a much lower chance of sending you to an institution for treatment and recovery.)
If you want to raise eyebrows among potential employers, then learn you a Haskell for great good. Or OCaml. It's not that anybody is using either in anger very much, but they'll mark you as somebody who isn't just following the easiest path to the Land of Promised Jobs. For a less-obviously resume-oriented approach, grab a Scheme (MIT, Racket and Chicken are all good) and work your way through SICP. (And make sure you watch the videos. Watch the videos even if you don't ever touch Scheme or read SICP. There's some head-asplodeeng stuff in there if you've never been exposed to a functional homoiconic language, and it will change the way you think about programming.)
