For a web server, a Linux machine with Apache comes ready to run, needing only to be configured. PERL (server-side) scripting comes with the package. If you are a hobbyist experimenting with web servers or an administrator of a low to medium volume server, I would not look any further.

High-volume servers may need a professional version of Unix, although I'm also sure the Red Hat people (or even your vendor) would be glad to set up Red Hat Linux for this purpose.

For those desiring a Microsoft solution, you'll need Windows-2000 with IIS 5.0. The NT-4 based IIS-4 does not have sufficient stability. Windows-2000 Professional can be used for this purpose, as long as you don't plan to host more than one site on an individual machine. The only real advantage a Microsoft solution would have is the ability to support the Microsoft-only technologies, such as active server pages. But there are alternatives to that in the Unix world, usually using Java server pages and Java servlets.