The reason that a lot of people prefer windows dedicated servers over those built on other platforms is that they get access to a wide range of software programs as windows happens to be the most popular system in operation used by web hosting companies. However, that may also mean you are restricted on running other applications that may be appropriate for linux for example, as they tend to be incompatible with windows servers.
What Startups Genius suggest you do is that, you should be looking at your requirements and compare them with the features that you get on a windows dedicated server as well as a linux based server. Normally, if you would like to be using loads of PHP scripting platforms, you will find the linux systems to be more robust for this purpose.
However, if your website would rather be using the ASP platform, you will have to go for a windows based dedicated server. So, it all depends upon your usage requirements as well as what you would like to be doing with your server in terms of the kind of website you would like to be hosting. You may seek the help of a technical person for further advice on the best server to go for.