A good language to learn would be one where you have access to a lot of interesting literature in its original language.
When a work of fiction is translated, you lose some of the poetry woven into the prose that the author intended.
If you learn German you can read Nietzsche and Schopenhauer. Nietzsche is seen a meme philosopher for edgy young men, but anyone who has seriously studied Beyond Good and Evil, Thus Spake Zarathustra or The Genealogy of Morals can't help but be impressed by Nietzsche's intellect and command of language and ideas.
If you learn Russian then you can read Dostoevsky, Tolstoy, and Turgenev.
Hungarian (Magyar) is another language you might want to look into. Politically speaking, Hungary is arguably the most right-wing and traditionalist countries in Europe at the moment. Hungarian (Magyar) is weird as fuck as a language; it is unlike any other European language and apparently, it is quite beautiful and very logical.
You could probably impress a lot of people if you spoke a non-European language fluently, but, from what I understand, it is quite difficult unless you are willing to put a lot of time and energy into it.