I have professional working experience on the following:
1.) VB (This Language has sent me in Canada, to develop an automation software for our affiliate company. This is good for Rapid Application Development on windows and If you want to exploit the MFC and WIN32 libraries.
2.) C# and VB.NET with ASP.NET. This is my start of my web programming. I have done software support and development on those. C# is pretty much the same on syntax with Java, but it has different sets of libraries. VB.Net, easy as Basic Language with the power of .NET framework on your hand.
3.) Java. This is what I'm developing right now. It is an elegant and mature language. Lots of resources and open source libraries. I had made several application on this. (Servlet, applet, jni, jdbc, tester tools to name a few)
4.) SAS. Proprietary Software from SAS Institute for Business Intelligence applications. This is a good development tool for data mining and warehousing. It is a mature system to gather and do statistical reports on big data sources. I also have a project on this right now.
I like all these languages. It boils down to what kind of project you want to do. The more technologies you know, the more you know the strengths and weakness of those languages. And you have more tools at your disposal.
(FYI: I'm building my career as a Software Architect)