Can't really see the answer being anything other than the SNES.
Fantastic game library and great hardware for the time. The Wii is a great console but in retrospect it was a bit disappointing. The SMG games were absolutely amazing but I feel like Nintendo's development was otherwise not up to its usual standard, and motion control wasn't utilized as well as I initially imagined it would be. It didn't help that Nintendo basically gave up on the system prematurely despite its sales success. I'll reiterate that it was still a great system, but hardly their best effort. The NES and N64 were also great but didn't have the well rounded library of the SNES.
The SNES was a combination of incredible first and third party efforts that has really only been rivaled since by the PS2. It was the golden age of JRPGs and gave us great games like Super Mario World, Super Metroid, Chrono Trigger, Final Fantasy VI, and Street Fighter II. In my opinion, no Nintendo console since then has been able to compare in terms of pure game quality and fun.
