The NES for me. It single handedly revitalized home gaming after the crash of '83-'84, it set standards with classics like Super Mario Bros and The Legend of Zelda, and it had so many great games. Pretty much everything on the market at the time was on the NES, save for 1st party Sega games, and even some of them, such as Shinobi and Afterburner, came to NES via Tengen... that's how popular the NES was in its day.
The SNES is easily second, followed by the Gamecube (loved it, even though it has by far the worst Mario game).
I love the N64 and Wii as well, but these were the only two generations where I felt it absolutely necessary to own another system, as there were so many great games on the market that didn't come to these two. Some would say the same for the GC, however there weren't very many games I cared about that gen that weren't on GC.
Now if you count everything the Wii has as far as backwards compatibility (all GC games), ports (Res 4 and Prime Trilogy) and Virtual Console in addition to its own library then obviously it has a major advantage.







