In my personal experience the most talented developers have been polyglots. Not that someone who knows only two syntaxes is not useful. It must be like musicians ... when you see a person get off the drums and pick up the guitar ... it just puts you in awe.
Most programming languages are essentially the same; skills are directly transferable and you just have to learn minor syntactic difference. I would think it would be much harder to master guitar just because one already mastered drums, or the other way around. Show me someone who has mastered computer graphics and say databases, then I'll be in awe.
But indeed, mastering more areas is even more impressive.