I'm stepping into very subjective territory here, but:
SNES - monumental 1st party games, monumental 3rd party games, controller was arguably the single most fundamental template for the industry's future.
Wii -The closest thing of a return to form to the SNES's first party software, only held back by sub-par 3rd party support and inadequate resolution output for it's time.
GC - dared to be different, maybe a little too different in the hardware department. Very unique first party experiences all the same. Controller was a double-edged sword.
N64 - Besides the N64 controller being borderline unplayable for some games, maybe I should put this a little higher, but this thing always felt more like the "Rareware 64" than the Nintendo 64. Not that that's a bad thing, but we're talking about Nintendo consoles, and the PS1 and/or Sega Saturn honestly feel more like successors to the SNES imo, and no, I'm not trolling.
NES - very little experience, not a bad system by any means, but it's most note-worthy games have had superior ports else where by now.
I can see the Wii U overtaking the Wii for me, the SNES is still a longshot though.
Bet with Einsam_Delphin: http://gamrconnect.vgchartz.com/thread.php?id=172355&page=11