I've always been kind of moved by this.
Voyager(s) have anthropomorphic qualities to it which aren't seen nor given to pretty much any other spacecraft ever launched, and they've been active for nearly 45 years now. That's predominantly due to the Golden Record and its encapsulation of humanity but also for things such as the family portrait of the solar system that served as the inspiration for Carl Sagan's "Pale Blue Dot" monologue set to Vangelis, just things that we'll never quite be able to duplicate again.
So many achievements to its name that can't be done for the first time again. It was the first to observe volcanic activity on another world, the first and only mission to complete a 'grand tour' of the outer planets of the solar system, the first and only to directly explore Uranus (1986), first and only to explore Neptune (1989), first and only thus far to cross into and explore Interstellar Space (2012). From 1977-1989 alone, it had collected enough scientific data to fill 6,000 editions of Britannica Encyclopedia.