Every form of media has some golden trinket in it's midst. Something that is brilliantly made, something that makes you think and something that, no matter how many times you revisit it, you'll find something new.
In anime, this golden trinket is Serial Experiments Lain. I've owned the DVDs since I was first able to acquire them and have watched them like no other. This series is one of the most brilliant animes ever made, if not the most brilliant.