The wisest move is to carry out a TCO. The term Total Cost of Ownership refers to the total costs to be incurred due to the operation of that system over a period of time, say five years. This cost would typically include, but not be limited to, software purchase & licensing costs, support, personnel training, maintenance and upgradeability costs (if any).

There are very few organizations in Pakistan who carry out deep statistics to see whether their IT infrastructure investment is cost-effective or actually pays back in the long run. Most companies skip this step, citing time and costs. In some cases lack of insight into such matters cause them to embrace a typical setup.

Unfortunately for them, their efforts may have paid off if they had adhered to some of the guidelines to consider when calculating the TCO for any system:

Acquisition & Licensing Cost: Type of license granted, period, renewal cost and the cost of purchasing the operating system itself. Linux is free or cheaper compared to Windows.

Training Costs: How much are you likely to spend on training the staff and the tech support? *nix training is considerable higher.

Hardware Acquisition Cost:
Check whether the operating system is hardware compatible with current systems. Don't expect Win XP to run on a Pentium I machine with 32MB RAM, Linux is more likely to.

Maintenance Cost: This can be calculated as the number of hours lost due to redundant repairs, performance tuning or tweaking.

Support Costs: 24/7, on-site trouble shooting, live support? Is the support free or are there additional costs?

Cross-Platform Compatibility: If your business requires cross-communication between two different platforms check whether the OS supports this or requires additional bridging software.

Stability: System down time may put-off
customers. Lay greater emphasis on
stability for mission-critical applications.

User friendliness: If, after basic training, the user still has to frequently access the manual or help, then you are losing precious productivity hours.

Depending on your environment and business needs, draw out at least three systems side by side (Windows vs. UNIX vs. Linux) and add up across them to see which solution would give the best trade- off. Depending again on your environment, you might like to give stronger emphasis to maintenance costs being a major factor, as compared to acquisition & licensing costs which startup companies would like to keep low.

In lieu of this, Microsoft has been recently openly advertising Windows Server 2003 as being a more cost effective solution pitted against its strongest rival the Open Source Linux alternative. Microsoft makes a bold claim backed by independent leading tech consultants such as Forrester and the Yankee Group. If you have come across the recent Microsoft ad placed in local newspapers and magazines, then you know what I'm referring to. Below are some of the many interesting findings posted on Microsoft's site:
"Equifax, a direct marketing service enterprise worth US$1.2 billion in internal analysis proved that Windows would realize a 14% cost savings over Linux on their mainframe systems.
Computer Builders Warehouse (CBW), who sell computers to various segments found a 25% saving in TCO when moving from Red Hat Linux to Windows, 50% reduced maintenance time, 50% consolidation in server population which  totaled $650,000 annual savings.
A Yankee Group study concluded that for large enterprises a total switch from Windows to Linux would be 3-4 times more expensive and take throe times longer to deploy as compared to upgrading Windows.
A BearingPoint whitepaper sponsored by Microsoft found that licensing and support do net significantly differ between Windows Server 2003, Red Hat Enterprise Linux 3 and Novell/SUSE Linux 8 and also found Windows Server 2003 to be cheaper in several cases.
A Forrester study concluded that Microsoft has the lowest elapsed time between a vulnerability disclosure and its subsequent fix and also found in another study that Linux training is 15% costlier than Windows. Secunia, a security website compiled statistics which show that Windows Server 2003 has 1.7 advisories per month compared to 7.3 advisories for Red Hat Enterprise Linux 3:'
As much as Microsoft would like to openly boast its superiority, a UK report prepared by the Office of Government Commerce proves Linux as a viable cost-effective solution generating savings.

Though this cat-and-mouse game may never end as long as there are Microsoft loyalists and Open Source pioneers, the tide is likely to swing to each side but albeit momentarily. The debate considerably puts the situation in to the spotlight and its now easier to make an informed choice. You are no longer bound to use Windows and Linux is not a free meal either.