Hard to say really but I like metaphysical movies and if I can only choose one I'd go for Labyrinth with Jennfier Connely and David Bowie. Saw it when I just a kid and it left a deep mark. Started creating a lot of labyrinths in school and giant ones at home on paper only tough....as of yet;)
Others are: eXistenZ Matrix, Thirteenth floor, Avatar, Truman Show A Beautiful Mind