Hardcore and casual gaming used to be referring to the amount of time spent playing video games, IIRC. Nowadays, a casual gamer seems to be someone who enjoys primarily easier/social gaming (farmville etc).
True, but I find it hard to say someone who spends 10 hours a day watering their crops on farmville (I know people like this) "casual" whilst someone who plays FPS twice a week is "hardcore".
To me a hardcore gamer is somebody who is interested in ranking in competitions and being top of the online leader board. Where their ego is directly associated with the game.
Or perhaps someone heavily into modding/mapping.
