For me, I'd say it's the sound of the spinning disc's close-up heard when Sam's first opponent in the disc wars throws it at him. Best heard through a good pair of bass-capable headphones, of course. The sound is sinister, letting you know that this is a weapon. Plus it has a great mix of both treble and base that just doesn't come through on anything other than the 'phones. It also shows you that the disc is spinning incredibly fast, even though you don't see it.

Second, I;d say the sound of the guy Sam first sees getting derezzed right afterwards. Only once in the movie do you hear this happening slowly enough to really get that this poor slob-and all of them when they get derezzed, have screams that themselves derezz as they degenerate into "bits", their voices getting rougher and rougher as they transition through 64 bits to primitive, rough-sounding 8-bit audio, and then to nothing.

You're welcome, DawnStar. I thought it was pretty awesome myself! I love the fact that the Lightcycle Rezzing In sound is made partially from flipping through a deck of cards! LOL! I'd love to isolate these sound effects...I think some of them would make great ring tones!