It depends on your goals. If your goal is to do a startup, then the obvious choice is to really master an entire web stack. For instance linux / nginx / python / html / css / javascript. If you want to do research in computer graphics, then you better learn OpenGL and C++ or .NET. Want to work in embedded systems? C. Scott's recommendation of C# & Javascript is a solid and pragmatic choice, good for those looking for…
Can you do without only Python and its framework for programming side? As someone new to programming, I find it mind boggling how folks suggest learning multiple languages. Or does it become natural after you know one language very well.
IMHO, you won't go wrong learning one language reasonably thoroughly as a starting point. In fact, I'd recommend it for several reasons.
However, sooner or later, you'll probably hear that another language might be more useful for another project you want to do, and maybe then you'll learn that second language too. As you do, you'll notice similar ideas cropping up, even if they go by different names or use different syntax.
As your experience grows, you start to think of each programming language as being roughly in this family or that family in one respect, and maybe being like these other languages or those other languages in some other respect. You also probably notice more what still makes each language distinctive, whether it's a few idioms that make writing a certain style of code easier, or maybe a couple of unique features that aren't widely available in other languages that are otherwise quite similar.
In the long term, it's these distinctions that make it useful to know several different languages. Even then, most of the languages you know will draw most of their tools from the same toolbox, and learning when to use a hammer and when to use a screwdriver will be more important than which brand of hammer or screwdriver you buy.