Ok, don't be shocked, but There'll only be about 8 - 10 machines, Max, for now!
I've decided to try and resurrect my old Gateway 2000 PIII 450MHz machine, It's got 384 SDRAM (PC100) and whichever HDD I choose to put in it - Either a 40Gb, or a 120Gb, but I'll probably put in both.
I'd also like to know about backing up - I'm guessing Raid would be the best option, but I have also known of backing up to DAT.
I'd like Backuping to be an automatic process if that's at all possible, as we usually forget!
I'll post a diagram of what I intend to do, shortly.
Edit: Here's that diagram (good old powerpoint