I might be considered a "hardcore" gamer due to my fondness for video games and my knowledge relating to them, but really, that's about it. I don't care about console wars, online competition, "gamer culture", or even game critics. I think the word "hardcore" itself implies something about mindset; someone whose life basically revolves around video games, or at least has a very strong mindset regarding them...which isn't the way I am. I just play games and enjoy them.
Incidentally, I wasn't always this way. I can say that I was definitely a "hardcore" gamer a few years back by most definitions. I was definitely on Nintendo's side and no other side, and I sometimes tried to convince my friends that the Gamecube really was the best system and the others were bad. Which was pretty foolish, considering I'd never even touched an Xbox or Playstation 2. Beginning around 2006, however, my hardcore attitude sort of gradually dissipated as I accepted the merits of other game consoles. I'm not sure exactly when I definitely decided not to be a Nintendo fanboy, but it probably came with my more encompassing "attitude overhaul" at the beginning of 2008. My getting an Xbox 360 at Christmas of that year was still quite a surprise to my friends. I supplied my 360 and both Rock Band games at the all-nighter I went to this weekend. :P