For the hard disk (2.5" IDE), I ordered a 250GB Western Digital Scorpio.
While I waited for the disk to arrive, I got ready to install the OS.
I'll stick with Ubuntu. I don't have a USB CD drive, so I'll try to install it from a USB memory stick. I followed the instructions here to make put a bootable installer on to my USB stick. The warnings about checking the correct device name are important! AFAIK the only way to be sure is to mount and list the device. Mine was /dev/sdb1.
I want a minimal server installation, so I just copied the netboot image and left it at that. I'll pull the packages I need from the network as I need them.
I initially tried
$ sudo zcat boot.img.gz > /dev/sdb1but that was giving permission errors. So instead
$ sudo sudid the job. I tried booting my laptop from the USB stick, but it said it was not a bootable device, so I followed the instructions on that same page to install an MBR.
# zcat boot.img.gz > /dev/sdb1
I tried again to boot my laptop. This time it booted to a prompt
MBR FA:Ummm... Back to Google. I found the answer here - first enter "a", then "1" and it launched the text-based installer. Good. Hopefully it'll do the same on the fit-PC.