Atari 2600 (1977)
If we’re talking revolutionary gaming consoles, the Atari 2600 would be near the top of the list. Although it wasn’t the first of its kind (that honor belongs to the Fairchild Channel F), the 2600 was the system that actually made ROM cartridges popular. Which meant that games didn’t have to built into units. Which opened up a world of possibility for home gamers everywhere.