C# is purely for work on Microsoft OS platforms. It’s Microsoft’s response to Sun Microsystems averting a takeover of Java by MS. If you learn C#, you’re stuck with Windows - great if that’s what you want to develop for, limiting if you intend to spend much time on other ecosystems.
Java dominates Android and FOSS development. Widely used, but not as much as some think.
On Apple systems (OS X and iOS), Objective-C dominates. Like C#, a must-have for the indicated platform, not much use elsewhere.
C++ is the Latin of software. Awkward, powerful, arguably dead, but a great starting point from which you can either branch to newer descendant languages, or to developing for legacy (loosely defined) systems.
Python, Ruby, and a few others are big for web development.
If you’re learning programming for _fun_ start with C++ or Java then consider something entertainingly esoteric like Lisp, Prolog, Forth, or newer equivalents (akin to learning Latin then Japanese, Thai, or Inuit).
Probably starting with Java makes the most sense, now there are other languages that run on the JVM, like Groovy and Scala.
But a well-experienced Java developer can easily make the leap to C# and Objective-C. I am learning Objective-C now for iOS, and once you get through the syntactical differences, it’s pretty easy to pick up. Most of the concepts easily map from Java.
C++ is the Latin of software. Awkward, powerful, arguably dead, but a great starting point from which you can either branch to newer descendant languages, or to developing for legacy (loosely defined) systems.
We're fortunate to have Bjarne Stroustrup, the creator of C++, here in the Lone Star State at Texas A&M where he has taught some freshman introductory courses. It's not unlike having Thomas Edison as a professor for basic electricity theory and practice.
I can't help but recommend his Programming -- Principles and Practice Using C++ book. I'm a crusty old programmer (C, C++, Java, Perl, PHP, Python, LISP...) but this book made me feel like a kid again. It was a joyful experience to rediscover the basics in a new light with a fresh start. Stroustrup's book presumes a blank slate and although he uses C++ as the tool, the lessons are applicable to programming in general. And a manner similar to Latin, C++ is a good fundamental language since so many of the newer OOP languages were inspired if not actually descended from it.
jonrick46: If you're looking to ease into programming and also have fun while doing so, I can heartily recommend this book.