Mine would have to be items of great value to biking in the long run.
1. TA Pro vis crankset/chainrings & Stronglight 49D for the most versatile, light and durable, low Q factor stuff around.
2. Campy sidepull brakes as revolutionizing good braking and control. A brake that unlike the Mafacs didn't need dedicated pivot posts on the frame. It may not be the best now, but at the time they came out, nothing else came close.
3. The Sturmey Archer AW hub for just being the work horse of the industry for epicyclic gearing for club bikes for I don't know how many years. (although my favorite is still the ASC).
4. Needle bearing headsets, for me either the Stronglight or Galli's. For those of us heavier riders who wore out ordinary headsets far too frequently.
5. Brooks saddles, love 'em or hate 'em. Tired of those hemmorhoid's, the bloody underwear? There's a shape for almost anyone's a**, and if you can get the seat where you want it, a pretty comfortable ride. And the design is virtually unchanged for more than a century.
Just my $.02 Happy trails,
Dan Artley in Parkton, MD