Call of Duty 4 is truly a magnificent piece of gaming, however short.  I agree with Hilbert that the sniper level with the ghillie suit, traipsing around Chernobyl, avoiding radiation, meanwhile taking out bad guys with the M107, is the best sequence ever put into a video game.  I also liked the 'death from above' level too, but YMMV.

We find ourselves a bit more appreciative of the X-Meridian, actually.  Subjectively, it was crisp and clean, unnoticeably immersive; all the action just pounds the ears into sweet submission.  The X-Audio, and its EAX mode, just puts too much reverb to be believable.  So off it went, and this is how we tested CoD 4, no EAX.  Once EAX was off, the experience was similar to the X-Meridian, pounding but enjoyable.  I won't mention the onboard solution, because it just cannot compete.  I'm reminded of that song, 'Let's make love, and listen to Death from Above.'