Pre-1980 Favorites:
ALL OF THEM! LOL But seriously, I think the turquoise Model L with PN-2 is the best cleaning machine. The Model L with the plastic bag chamber (1968 and newer) has the best airflow of any Lux machine, and the PN-2 was designed to be effective when used in conjunction with a cleaner outfitted with a 535 watt motor.
Of course, the Model G is probably the quintessential example of Electrolux quality at its best. Gorgeous in design, powerful suction, and whisper-quiet. The Model G is only paralleled by the Model XXX, which, in my opinion, is the machine that introduced Electrolux as a brand of choice for so many homes for so many years.