Which sci-fi titles (movies, books) do you consider comforting, cozy, something you come back to from time to time? For me, I guess it is The Matrix. Still holds up to this day, gets better with every re-watch, and gives me a sense of peace when I need it.
The books Walkaway (Cory Doctorow) and Accelerando (Charles Stross) both give me nostalgia for a time when the future seemed like an exciting challenge instead of an unbearable one.