It depends on different things. Since this is about consoles, I can't pick one of the game boys, which would probably be my most nostalgic choice. Anyway, it's about dead even between the SNES, n64, PS 1 and 2. In order... SNES, n64, ps 2, ps 1.

As for the ps1 backwards compatibility thing with the ps3, **** sony, seriously. You can emulate a PS 1 with a cd player and an avocado. PS 2 emulation takes a ****ing super computer. The PS 2 is one of the highest selling ****ing consoles of all time, to avoid backwards compatibility is just a slap in the face. That and they wanna rerelease them on the Vita and shit...