In the line of the failure thread, which is the biggest success, both handheld and home?

Would it be the NES/Famicom for rebooting the video game industry and making Nintendo a household name? The GameBoy for starting Nintendo's dominance in the handheld market and carrying them through the tough times when Sony was around? The PS1 for setting up Sony as a dominant player in the console arena, or the PS2 for being the most sold console in current history?