hmmmm, tough one. I started gaming on a PS2 as a kid, me and my brother used to love doing galactic conquest on Star Wars Battlefront II, that might be some of my earliest memories of multiplayer (that and lego star wars), also Simpsons Hit & Run was a great game and the daylevels in sonic unleashed i love, I have memories of going to this summer club thing and there was a gamecube with luigi's mansion and sonic mega collection I have fond memories of the sonic 2 special stages (it would be years later before I played the orignal sonic games on vc and I love them btw) then I my brother got a ds and then I did after and we both loved Mario Kart DS (still my favourite game in the series) pokemon platinum, new super mario bros. also remember being at my cousin's house and playing MKWii and having it blow my mind in comparison to DS, then getting a wii years later and being really spellbound by mario galaxy, smash bros brawl, virtual console games (Ocarina of time, the sonic mega drive games, donkey kong country, Lylat Wars, mario kart 64, zelda 1 on nes, my brother loved chrono trigger, super mario bros 1, 3, world, 64, metroid nes love them all).
so yeah the Wii of all consoles really built my gaming identity, but I already had strong ties to the medium and still do, even expanding outside of nintendo games to have many consoles now (Xbox 360=arkham city, portal, Game Boy=tetris, mario land, 3DS=kid icarus uprising, resident evil revelations, GameCube=Sonic Adventure DX, Smash Bros Melee, PS3=arkham asylum, infamous, uncharted, xbox=halo)
so basically I consider myself a fan of all 3 but I can't help but get more excited for nintendo games, also I intend to buy a good pc in the future since I have played the original half life and counter strike and tem fortress 2 on my laptop and really want to experience those games properly because they're great.