I find two big advantages to SCSI. They are:
1) Speed. Yes, they're fuckin' fast. But so are the newest IDE drives (well, sorta, anyway).
2) Reliability. SCSI drives are, plain and simple, engineered better than IDE drives. This is one of the big selling points to me, and I probably didn't note it well enough. But SCSI products are superior to IDE in nearly every single way possible (with price being the big downside). Hence, SCSI for the main disk.
I know I mentioned rounded cables in there, Tony

Like I said, they're definitely an option, but I'm going to see how it goes first. I'm pretty good at making ribbon cables move the way I want them to, especially in a tidy setup (like this box will be). I'm not overly concerned about it, but they're definitely a possibility. I'll almost certainly use a rounded cable for the floppy, and I'm still debating over whether or not to use them for the hard drives & DVD-ROM. We shall see.
As far as backup, this is something that will come in the future. Basically, I'm going to do RAID mirroring, but I'll need a card that will do both IDE & SCSI. Then I'll just buy dupes of my drives and set that up. This is one of the planned upgrades - probably taking place around next fall. In the mean time - I tend to live my computer life stupidly dangerously. I have no backup on any of my machines. Beat that.

Though I used to ghost my hard drives back in the Windows days. Oh well.
BTW, the place to get rounded cables is
http://www.pcmods.com - they have them cheaper than ThinkGeek (TG is just a reseller for PC Mods anyway

).
[edited to remove typo]