I do not think Interstellar is Nolan’s best work, but it might be my favourite movie-going experience of his works. The reason is Zimmer’s score, I think his best work in a Nolan film, and the sound mixing; a dynamic mix that can be near silent, or near-deafeningly loud, never afraid to let the score swell and become part of the scene, whether with emotional melody or sheer power. The movie sounds and feels as large and as overwhelming as it looks; it lets me accept the movies conceits, as by the time they become unavoidable I’ve already bought in.
The Dark Knight is exceptional because of Ledger, more so than I want to give credit purely to Nolan. Batman Begins, I view weirdly; I just don’t think of it as a ‘Nolan’ film. Its a pretty standard, if gritty, superhero origin story plotted and executed competently, and while apparently that is really difficult, I can’t see much about it that is unique to Nolan.
Inception is my pick. I distinctly remember, as the film reached the climax of the heist and they activated the ‘kicks’ at each level, being really really happy to have paid to see a movie that didn’t treat me like an idiot. It said “hey, heres multiple threads with perhaps not entirely clear resolution. You can track them, you can come up with your own conclusions, I believe in you” and that was pretty bloody rare back then, let alone now.