I grew up with Nintendo, between the NES, SNES, and Gameboy early on, and later the N64 and Gamecube. My first non-Nintendo system was the original Xbox, and even though I now own an Xbox 360 and PS3 at this point, I will always be a Nintendo fan as well.
I own a Wii U and 3DS, but I am also still looking forward to the new Microsoft and Sony consoles, though its highly unlikely I will get both if they both release this year, I may get whichever one has a better launch lineup. I just see no reason to limit myself or my game choices to one manufacturer.