C# is a modern, multi-paradigm, feature-rich and evolving language. It can be most intriguing for a young programmer because you can play at various levels of abstraction (from unsafe all the way up to LINQ) and express computation in various ways (you may do a Lambda expression for one thing and a method for another). And you can use it as a scripting language, as well.
Young programmers running Windows can always get Visual Studio for free via DreamSpark. Young programmers running anything else can get MonoDevelop. There really is no excuse to skip this incredibly productive language.
The plus side? migrating from C# to other paradigms should be simple. And the C# user community is just as friendly as any other free language's (minus the "RTFM, N00b!" replies.)