Here are some classics that became classics by longevity, each superior in conception, design, materials and serviceability to everything else available in its class:
ROHLOFF HUB GEARBOX
Comes with an effectively unlimited guarantee as long as you change the oil once a year; no one has yet worn out a Rohloff box.
BROOKS LEATHER SADDLE, ANY
Shapes to the owner over the years, should be buried with him.
SHIMANO DEORE COMPONENTS
Common as dirt, not quite as cheap, soldiers on forever. In some components you really do not need anything better than Deore because it is impossible to conceive of a bike that will outlast the component.
LEDS
The first proper, useful bike lights -- and they last forever!
SKS RENNKOMPRESSOR
Best field and garage pump, wooden handled still but otherwise modern, infinitely rebuildable, moves a lot of air fast, will pump to 16 bars (!) if you have the shoulder for it, the choice of all the best racing teams.
ZEFAL HPX FRAME PUMP
The classic, infinitely rebuildable, actually pumps air (which cannot be said for many of its trendy successors).
MAGURA HYDRAULIC RIM BRAKES
Superior to disc brakes in action, truly fit and forget, no service required, ever, and light on brake blocks and rims, thus cheap to run. Gets my vote for the Best Bike Brakes in the World.
SCHWALBE TYRES
An amazing tyre company, they brought back the balloon with the Big Apple, and their Marathon Plus is almost a generic thornproof tyre. Heavy on science, all their touring and fat tyres last unconscionable distances. Also a maker of fashionable tyres for the trendies. Not expensive when you consider how long their tyres last. If I were forced to make a personal choice of their most outstanding tyre, it would be the 60mm Big Apple Liteskin, with the Ultraleicht Type 19A racing tube: huge volume of air for comfort, very low rolling resistance, nowhere near as heavy as one would expect, a wonderfully secure tyre at speed for both comfort and directional stability, lasts forever, folds for touring, the "racing" tube is for practical purposes as tough as the normal one -- exotic yet ultra-practical: it somehow sums up Schwalbe.
Andre Jute