One of the most frustrating things I have encountered in assessing the IT needs of my company is that since I cannot always predict what I will need next year, when next year arrives, I lack the infrastructure to accomplish my tasks. When I first starting running Windows 2000 on a main office computer, I thought 'gee this is pretty good, and much better than Windows 98.' However, it was only a matter of weeks before I ran into a situation that what I needed was really Windows 2000 Server; I certainly did not have the money for that, so I did without. This happened repeatedly over the course of several years, and never became a fully acceptable way to operate.
I have a colleague that serves as a Windows administrator for an organization; he does not make purchasing decisions but can only 'advise' those that do. The network was originally Windows XP Home Edition with one Windows XP Professional computer functioning as a file server. The system has many, many problems, partly due to weak enforcement of use policies and non-centralized user authentication. The problem is due to Windows XP Home not being able to join a domain with the domain controller providing access control to the network. All admin involves sneaker net deployment to the individual clients and much redundancy in human-computer interaction.
The organization then bought a software package that required all users to essentially be simultaneously connected to the file server. Since the network size exceeded the 10 user max in Windows XP Pro, productivity crashed. The decision was made to purchase (for about $1000) Windows 2003 Server to handle the simultaneous connection issue. Existing software did not work on Windows 2003 Server, so the Windows XP Pro box was kept to serve data for those applications. The clients are still XP Home, so a domain controller is still not possible. Clearly, the licensing cost of upgrading to XP Pro for the clients is prohibiting proper and efficient network implementation.
In contrast, Linux operates within a model that can be summarized as ``get things done.'' It is a workhorse system, not a manipulated means to a revenue stream. Last year, I needed to use an application that communicated in parallel with other nodes on the network using Kerberos. In a matter of hours, I installed and configured the Kerberos server(s) and the clients. No additional software purchase was necessary. Similar cases arise nearly weekly in my business, and I've yet to have to purchase a higher class license or additional software for getting things done with my Linux based systems.