Part 1: Choosing your OS
The choice of OS to use for a server is huge, there are free and paid for options.
For the free options you have mainly Open Source options that are Linux-based OSs such as:
Red Hats Fedora Core
Mandrivia's Mandrivia Linux
Open Suse, Fedora Core and Mandrivia are all mainly Desktop based OSs but also have the capability to be used as Web, Email, File Servers and more, they all have a graphical Desktop so configuring the server is easier to do.
Ubuntu Linux comes in to versions the standard Desktop Os that can be used as a Server or the dedicated Server version. The Desktop version of Ubuntu has the graphical Desktop but can also be configured to be used as a dedicated server by uninstalling all the desktop applications, where as the server version is a dedicated server OS and does not include the graphical Desktop and is configured using the CLI so it's basically like running the pre Windows Microsoft DOS OS and having server applications installed that don't have a graphical interface.
If you go the Open Source route with your server then I would recommend staying well clear of Ubuntu Server unless you are used to using Linux and feel comfortable using the command line.
There are many more free Open Source OS's than the ones I've mentioned that are available but mentioning them all would take up to much space.
For the paid option you have mainly proprietary OS's but there are some Open Source options that offer paid for versions of their OS.
OpenSuse is a free download from there website but they also offer a paid boxed option that includes the DVD and CD needed for installation along with a user manual and 90 days of free support once you register your installation.
Mandrivia also has a paid option that gives you more drivers than the free version and support as well
Red Hat and Novell also offer dedicated server OS's but they are mainly used in Enterprises and would be impossible for a consumer to get hold of.
Microsoft Windows XP/Vista/7 can all be used as a simple web and file server and with the right third-party software could also be used as an email server.
Apple's Mac OSX Server (but as the Advent 4213 is a non Apple piece of hardware that is not an option)
Windows Home Server meant as a simple Home file and streaming media Server, mainly comes on dedicated Home Servers but can sometimes be picked up on ebay as just the OS without the Server Hardware.
Windows Server 2000/2003/2008 are all ment for businesses and enterprises but can still be picked up by the consumer on ebay.
Compared to Windows XP/Vista and 7 Windows Server is a dedicated Server OS but is still user-friendly thanks to the familiar Windows Desktop. Windows Server can be used as a simple Web, File and streaming media server as well as being used for email (using Microsoft Exchange Server), it can also be used to push email to BlackBerry Smartphones using the free BESX software or the paid for BES software.
For this project I have chosen to go down the Microsoft Windows Server 2003 Enterprise Route with Microsoft Exchange Server 2003 Enterprise and BESX as I've got a BlackBerry Smart-phone. I'll also be adding a wordpress.org Server as it's a free piece of software along with a phpBB run forum (free software again) and a MySQL Database Server (also free).
In part 2 I'll be covering configuring Windows Server and installing Exchange and BESX Servers as installing Windows Server is exactly like the installation of Windows XP.