You will need a system board of some type to run your server. What type of system board depends upon what you need your server to do. Here I will be focusing on having a web page and maybe an FTP (File Transfer Protocol) site. So we will be looking for a system board that has only what we need to accomplish those goals.
For this I will recommend some ARM (Advanced RISC Machine) products. These have a very low power consumption, Low priced and easy to use. Unlike a PC system board you usually get all the necessary pieces on the board, CPU Memory, Video etc.. With a PC board you would have to purchase those to even start having an operational web server. Cost of these boards is from $35 to $80 depending on what you choose.
Raspberry Pi Model B $35
Beagle Bone Black $45
Cubieboard $54.50 to $64.50
All of these choices have an 10/100 Ethernet connector, 512MB or more RAM and at least one USB port. There are other boards that can be considered as well. Some are expensive like the Panda Board, Beagle Board and the Trim-Slice. There are more of the ARM boards appearing by the month nowadays.
All of these use a SD card or Micro SD card as their primary storage device. More on these later.
Some sort of case or mount. I think it is important to have these boards in something to give them protection from Static and from accidental shorts.
You will need an available port on your router to plug them into. You can go wireless but this always more complicated, and in my opinion, not as reliable as a good old cable.
All need a Power Supply. It is usually best to buy one with the board at time of purchase.
You will also need at least a keyboard for setup. You can borrow the USB keyboard from a computer if you have one.
How much power/RAM do I need?
Some people think they need a lot more power than they really need to run a web server. A web server is basically a device that lets you remotely view an electronic document. This does not really take much in the way of speed or memory. Your outgoing (upload) speed can be more of a problem than the power of your board.
A static web site needs very little to have it run efficiently. An example of this is that a web site can be hosted from within certain routers. these usually only need 32+ Kilobytes to work properly and the processor speed is only about 200MHz. So the speed with which your “pages” can be shown or “served” depends on how you want to setup your site and the connection that the site has to the Internet.
This site is using WordPress which needs quite a bit of power to run. The speed of my site has two bottlenecks. The Raspberry Pi does not run the database very fast and my outgoing speed is only 100Kbps. So if I overload a page with pictures it is going to slow down a lot. Pure text is a bit faster. But WordPress makes it very easy to update the page and requires no other software to accomplish the update. A static set of pages would be faster on the RasPi. Static pages would require me to either edit by hand, use a WYSIWYG editor or buy software to edit the page. I would also need an FTP utility to send the update into the site.
One of the other boards that are faster would run this site better, but more memory than the 256MB Raspberry Pi would not have much effect, other than the ability to put more onto the device for other uses. It all fits nicely into the 256MB for now. To illustrate this I moved the site over to a 512MB Raspberry Pi. There was no difference in the speed the site ran at, none!
The Site was moved back to the 256MB rev.1.0 Raspberry Pi after about three weeks.