I prefer to sit down, but never in an "easy" chair. Easy chairs are great for racing games though.
If I play an arcade cab, and there is a stool nearby, I will grab it and sit down.
At home, for intense games, I choose to sit on an automan/footrest.
Although, it seems light-gun games are easier to play while standing, as I feel less fatigue. The only bad thing about that is, well, my TV sits too low when I'm standing up.
Ahhh...the problems with modern day living.
