What you've got is two almost entirely separate systems. On one hand, the Intel system has the PC800 RDRAM, SCSI while the AMD system is comprised entirely of IDE drives.
Decide on which one you want to go with: IDE or SCSI? Another thing that I've noticed is that you put the drives in pairs, which COULD potentially indicate some kind of RAID setup, I presume. (could be wrong, but it IS possible.)
And probably the last question that I would ask or try to have you answer is: "how much?" $$$$ or $? In the end, it will be your finances that will determine what you will or will not get.
Everything in computer stems from cost, and then you have to decide on the components based on that.
Like if you want a really really HIGH end system based on the x86 structure (i.e. not HP, Alpha, Sun, SGI, etc.)
I would recommend something like this:
Dual AMD Athlon MP 2000+
Tyan S2462NG board
Two GlobalWIN WBK38 (or your favorite HSF)
2048 MB PC2100 ECC CL=2 DDR SDRAM
IBM (or Seagate) IC35L018UWPR15 15,000 rpm, 18.1 GB (x6, for a RAID0+5 setup)
3D Labs Wildcat II 5110
Adaptec 2110S SCSI RAID Card
10x SCSI DVD-ROM (also serves as CD-ROM drive)
Sound card, keyboard, mouse, speakers, etc....up to you.
Of course...not everybody has nearly $8,000 US ($12,000-13,000 CDN) to blow on a comp system.
So...up to you.
If you're looking to mirror your data, then drive size is important. If you're looking for performance, then the size of the individual drives is not as important. If you're looking for both mirroring and perforamnce...then you ask yourself "How much space am I going to REALLY need online and how much of it can I putt away elsewhere (i.e. on a different system if possible.)?"
or...if you have lots of money to burn as well, why not get a 1U rackmount or 4U rackmount (1U for space, slide it in between other things, hardly noticeable/ 4U to fit your awesome video card.)
Also: advatnage for IDE - cost. Advantage for SCSI: low CPU usage on I/O operations and expandability.
For more hard drive information, my recommended site: http://www.storagereview.com
Hope it helps. Happy hunting. If you need more from me, feel free to email me at alpha754293@hotmail.com