What games are those? If you do get that motherboard you cannot have dual ATI GFX system. If you do want a upgrade path with ATI GFX buy the same motherboard as me. Unfortuantly Nforce and ATI 3200 chipsets aren't compatible with each others dual card configs (fine with single though) If you want upgrade path with Nvidia's buy that motherboard you've mentioned, but replace GFX with 7900GTX.
If possible I would consider a dual core CPU - Quake 4, Call of Duty 2, Battlefield 2 are some games with Dual Core support. I noticed DVD shrink uses the two cores (probably Windows sharing out load to both cores) Photoshop also will use dual core. I would swop that Asus ATI for another, they're all the same so get the cheapest. Powercolour or Sapphire for example. Get plenty of RAM. 1GB as a minimum, but because of pricing and issue of slower memory performance when using four sticks I would go for 2GB straight away - 2x 1GB modules (PS needs it!)
That PSU should be enough, HD's will work (not that I would trust Maxtors)
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but I would buy a SATA for boot drive (noticed performance difference between the three I have, the two smaller drives are 7200rpm but PATA) Don't need firewire card, motherboard has them..unless you need more ports
You need hard drives, optical drives, power supply, monitor, keyboard, mouse, soundcard...depending on what you're going to salvage from your existing components, or build a new system and leave the other system in working condition.