Good point. To me, "hardcore" is when I'm asked to put in hours that could do harm to my real world priorities (i.e. if a guild says I have to lose a lot of sleep or get kicked when I have work tomorrow, or if I need to give out my phone number so officers can find me IRL, it's too much), BUT the guild is able to progress to a very high level when compared globally (even I've done server firsts, but it wasn't on a high ranked server).

Casual just means you play. Doesn't matter if it's 1 or 24 hours a day, you're just playing. You don't have to be any good to be casual.

Hardcore casual is when you don't eat, sleep, and breathe for a raid, but you still do well (similar to what Ms. Stickney is discussing). It may have been different in the old days of raiding, but the PvE in games these days has gotten very easy and people STILL stand in the fire. If you've got brains to move, do some research on your class, and use your fingers instead of your face to play, you can probably pull off hardcore casual ;P