1x 320GB for /boot and /backup
4x 200GB on RAID5 for /home, /usr and /var
They are 512MB sticks
That's a stock Intel fan (made by Delta Electronics). It looks like 80mm, but then core 2 duos have a TDP of 65W. SETI@home and climateprediction.net keep both cores at 100% all the time and the heatsink temp never rises above 52°C with the fan near minimum speed. The northbridge is more of a problem hence the 40mm fan glued onto it.
It's a 4U case, I had to ditch the original hard drive cage since the discs overheated within twelve minutes (five discs with 2mm spacing and no cooling, great design!), I made the fan bracket for the 40mm fans above the discs. It wasn't that hard to fit it all in because there's no chunky PSU as it runs on 12V - you can see the DC/DC board next to the two 120mm fans.