I am going to say:
Both
I would also say:
- Perl - systems integration, general toolbox
- Python
- Smalltalk - pure OOP
- Scheme - functional and multi paradigm (and the book and on-line lectures Structure and Interpretation of Computer Programs) -- perhaps F#
- C - OS and driver level
- Objective C - iOS
- SQL - database programming
and I would add:
- Prolog - logic based programming
- Tcl/Tk - easy scripting of cross-platform GUI applications (Unix, Windows, Mac)
and read up on Snobol4 for a "string based" pattern matching and backtracking based language.
Each of these will give you different insights into programming. Especially Scheme and the attendant course material. You will probably NEVER use it in a commercial program, but it will make you a far better software engineer or developer. Smalltalk will give you insight (for example, "if", "while", etc. are not fundamental, and can be expressed using normal OOP methods). Once you have Smalltalk under your belt, Objective C and Ruby will be VERY EASY.
Perl (perhaps Python), C, SQL are vital "daily" skills.
Java is not "slow" when compared to C#. Indeed, the JVM is available on most platforms -- from phones to Mainframes! C# is mostly limited to x86 Windows platforms, and is a much smaller performance band.
Most programmers know a lot of languages -- Figure that you will have a working knowledge of at least 10.