I think I'm on the same page as most folks here; NOS is generally pointless and expensive if you actually build those parts onto something and ride your bikes. I occasionally buy something NOS that is unobtainable or difficult to find used, or is just a decent price. As Mark mentioned, more obscure brands can be inexpensive even new.
I actually love the challenge of taking parts that show some wear and making them good. Either by just cleaning, greasing etc, or breaking out the fine sandpaper, buffing wheel, or enamel paints! Getting them presentable, or even just 'in keeping' with the rest of a build is really rewarding, more so than just opening an old cardboard box and bolting it's contents on to a frame.