Yay! GLaDOS is back up and running after the old hardware conked this afternoon. It's a downgrade on CPU (from a Core2Quad to Core2Duo), unfortunately, but I managed to up the RAM to 6GB with a few sticks from the old server.
Best part: I didn't even have to reinstall. I just cloned over the drive with GRUB and the root and swap partitions over, moved the big data drive...and it just booted. All services are back up and working.
Added the little MacGuyver fan to keep the HDDs cool since they're cuddled up next to each other for now (ordered a bracket to move the second HDD from the 3.5" floppy drive bay to the 5.25" bay).