Personally, I've got to go with Nintendo. I grew up with an NES controller in my hand. Fell in love with gaming on that machine. So many hours spend rescuing princesses and blowing up robot-masters. Then the SNES came out and perfected everything the NES did by making it all better: Better graphics, better sound, bigger games, better controller, and more reliable hardware.
Got to say, I wasn't a big fan of the N64, though. I just can't stand that controller. But when the GameCube came out, they fixed the controller problem, and I experienced a lot of what I missed. In fact, I appreciate the GameCube a lot more today, than I did then. There really are some gems on that system that a lot of gamers overlooked.
Fast-forward to today, and the I still play my Wii. A lot of hidden gems to discover and fall-in love with, and when done right, motion-controls really are a fresh way to play games. Unfortunately, to find those gems, you do have to dig through a lot of crap; but in Nintendo's defense, most of that crap was not produced by them.
And the Wii U is looking more and more like my first choice for a console when I get a next-gen console. I'm pretty excited for the new Zelda, New Super Mario Bros. U, New Super Luigi, Rayman Legends, and others.
Let's also not forget that Nintendo absolutely rules the handheld scene, and always has.