A charity I volunteer for wants a file server for their mostly Windows machines (about five XP and 7 machines, with some Mac laptops every now and then). For the server, I have a PC with an Intel Core 2 Duo 3GHz proc, 4GB of DDR2 400MHz RAM, and a 500 GB HDD. (I should point out that they do not currently have any server - they are just using Windows to share a folder on one of the PCs.)
What is a linux distro that is easy to configure for Windows file serving yet stable and secure enough to protect sensitive data without an expert sysadmin?
I'm guessing that a Debian distro would probably fit the security bill, but I don't know of any tailored to novice sysadmins.
Also, are there any killer apps for making this easy to administer and set up (as a Windows file server, in particular - this answer is a good example)? Would FreeNAS be sufficient? Once it's all set up, what are the minimum measures I need to take to keep the data secure?
I found this somewhat helpful answer, but it's not specific to my question of just getting a secure file server up, running, and maintained.