Let's see. How many discs would it take if you installed a couple of copies of Windows XP Server, Office XP, Microsoft Works, Visual Studio.NET, Active Perl, Visual C++, FORTRAN, PHP, MS Proxy server, a couple of copies of MS SQL Server, a copy of Mozilla, Exchange server, etc, etc, etc?? Because basically that's what you get on 3 RedHat CDs.
You get a few different GUI desktops which would be the equivelant of a couple of XP installs, you get several programming languages, a few different office suites, several browsers, many server applications, a couple of SQL database servers, and many many more applications I have not mentioned, not to mention 10 times the number of cute time waster games (probably more than 10 times). Let's see Microsoft try and fit all of that on 3 CDs...