[CentOS] Slightly OT: which hardware for CentOS file server (Samba, 2 To storage, 50 users)?

Hi,

The language lab from the local university has contacted me. They'd like 
to have a low-cost file server for storing all their language video 
files. They have a mix of Windows, Mac OS X and even Linux clients, 
roughly 50 machines. The files are quite big, and they calculated a 
total amount of 2 To of storage.

I'm not very proficient with hardware, meaning either I'm dealing with 
remote servers in some datacenter, or otherwise I install CentOS 
desktops on any hardware people throw at me.

Since the aim is lowcost, would it be wrong to install that fileserver 
on a no-name desktop PC with a 64bit processor and enough RAM, and then 
simply put 2 x 2 To hard disks in it, either with a mirroring RAID (can 
never remember which does what in 0, 1 and 5) or some rsync script 
regularly copying over the first disk to the second? Or do you have 
something more apt to suggest?

Cheers from South France,

Niki