C# is Microsoft's C++/Java variant. I don't know if it ever really took off that well, but I do know it's what you write games in for XNA.
One language I hear a lot about these days is Python. Seems like that's on the rise. Also Ruby on Rails, but not as much. And of course PHP is huge.
For my money, I'd do everything in Perl if I could.
But a lot of what makes a "good" language to learn depends on what kind of development you want to do.
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Black Turtle spilled my diet soda!