It's hard to answer this question, because on one hand I really love the Wii and 3DS because they combine giving us new gaming experiences with letting us relive the old. Finally we're getting backwards compatibility with Nintendo as well
However, I've been there when most of these consoles were out (didn't own or even play all of them, of course, the 3DS was my first ever handheld), so I have a lot of fond memories. And I think the console that really stood out to me in my years were the N64. I was 14 when I bought it. I had gotten my first job, saved up money steadily until I had enough to go out and get it. It's the first console I owned where the money didn't come from birthday or christmas gifts, so it was a very proud moment for me. The games were amazing and I'm upset that my controller has become so stiff and hard to play with, because some of those games are still not available on the wii

(Donkey Kong 64, Banjo Kazzoie, etc)
So part of me wants to say the wii because of backwards compability, but another part of me wants to say the N64 for being awesome, lol