Very nice rig. I'd recommend you get the Asus board with the NForce chipset rather than the A8V (I've had some freezing problems with mine). Out of curiosity, why do you need the three hard drives? I'd just get two big-ass SATA drives and dump the ATA100 since it's a third as fast.
As for a sound card, I've got a SoundBlaster Audigy 2 ZS, but it's kind of a POS. I've heard nothing but good things about M-Audio gear, so I'd recommend
this.