Personally I like Sony's consoles best. They seem to have a wider variety of games and games I like. They're a good balance between MS and Nintendo I think. You have the casual, the hardcore, and some good indies.

I take a heavy dose of Playstation with a sprinkling of Nintendo. Caught up on my WiiU backlog this Summer when I got it but after that it's just going to be used for Mario Kart and Smash with friends and of course Zelda a year and a half from now. Playstation first party and free games occupy most of my time with some 3rd parties (more than usual this year and Destiny will be re-visited frequently)

Coleco.

I consider myself a Nintendo fan first and foremost but I play primarily on Sony's consoles. I did buy a Wii U recently and have enjoyed playing those killer apps I longed to try such as Super Mario 3D World, NES Remix and Mario Kart 8. With Diablo III and Infamous: First Light on the way, the rest of August will see me back on PS4.

Nintendo. I must be nicer to them. I wouldn't want to hurt Iwata's feelings.

I have to go for Sony.

I grew up with a SNES and Gameboys, but when a game left its mark on me, it was a PS game most of the time.

Silent Hill 1, 2, 3
Final Fantasy IX, X
Uncharted, The Last Of Us
Killzone 2...

Don't worry, I also played games I love on other consoles: Xbox has Halo 2 and Alan Wake, and Nintendo has Pokémon, Fire Emblem, etc...

But overall, my most memorable gaming experiences were on PlayStation.

i refuse to vote. i most energetically advocate for indies over any of the big three.

You chickened out...  You know that based on the question itself, you should have an answer.  

Let's hear which of the three you would pick if you had to choose then?

Main - PS4
Secondary - Wii U

Nintendo is my first priority. Most of the time i will find great entertainment in the PS consoles, but the Nintendo games are the ones i will remember 5 years later. PC is also important to me.

So
Nintendo>SONY=PC