If you are more into single player experience, then you must try BF BC2 if you haven't already. I got BF3 recently with the Humble Bundle. It is good as a single player, but not great in any way. BF BC2 is so much better, because the characters are so well done, the BF3 characters are pale in comparison. I played BFBC2 at least 7 times through. You might even also look at COD Modern Warfare 1/2/3 single players have awesome characters and story lines.
For cans and DAC/AMP, you might just read the intro of this thread. It tells you the complete story. For long gaming sessions I can recommend the AKG K7XX line. Very comfy.