Without a doubt, Rossellini's War Trilogy is the greatest box set Criterion has released. Dave Kehr said it much better than I ever could, but let me just add that you don't need to look any further than this set to explain the importance of Criterion in film history. There are other things Criterion does well - highlight notable and overlooked modern films, present classics with excellent supplements that place them in a new light, impeccably package and legitimize the physical product - but the most vital impact they have had over the last decade is on truly significant works that were previously unavailable or underavailable, that is to say only presented in poor transfers or even decaying prints.
Rossellini's War Trilogy kickstarted not only neo-realist cinema and inspired three generations of filmmakers, it single-handedly revived Italian cinema and invigorated European film after the industry had been decimated in the war. There are only a handful of films in the collection that are more important and none of them were as desperate for an impeccable and high-profile release as these three. Rome, Open City, Paisan, and Germany Year Zero are all masterpieces and must-sees, and this set stands among Criterion's best, most significant releases.
Rome, Open City
Germany Year Zero