My three to ponder:
Original Stumpjumper (c.1980)- started bringing (quality) MTB's to the masses
Pace RC100 (c.1990)- no compromise racer, with some (at the time) groundbreaking kit and a bespoke frame to incorporate it.
Orange 5 (c.2000)- a design that is simple, low maintenance and has stood the test of time. Loved and hated in equal measure, but becoming iconic.