Java: plentiful well paying jobs, good/great tools, good/great runtime. Personally, I like boring, predictable, "easy" (referring to low cognitive overhead of statically typed languages in general) for work, and save the fun stuff (lisp/scheme in my case) for personal projects.
This is how I feel about C# and .Net - they are relatively easy to hold in your head, the tools are excellent for the language, and there are plenty of decent paying jobs.
There is very little to trip you up in C#, for my first project in it I sat down and started churning out code and looking stuff up when I got stuck. Try doing that with C++ and you will end up with a hole lot of trouble.
