My desktop OS: CentOS 4.2
I have been a Unix and Linux system administrator for more than 20 years, and have worked with many different operating systems. Over the last several years I've spent a lot of time with various versions of Red Hat Linux and Fedora Core, and I'm the editor of the Fedorazine online magazine. I run a Web consulting company, where I maintain several production servers for Web and email, and I need to have a stable production Linux environment for them. I chose to use CentOS as a platform for the servers, and since I already had a commitment to maintaining a number of different servers in CentOS, I decided a while ago to start using it on my desktop as well.
The CentOS operating system is essentially a clone of Red Hat Enterprise Linux. The CentOS people take the source RPMs for Red Hat Enterprise Linux (which are available under the GPL) and recompile them, taking out all of the branding elements of the OS and putting it together as a full distribution that for all intents and purposes acts just like the Red Hat product, but does not have support from Red Hat. Several other distributions are constructed in a similar manner, including White Box Enterprise Linux and Tao Linux. The current release is CentOS 4.2, which is equivalent to the Red Hat Enterprise Linux 4 release, with a number of patches applied.
CentOS in operation is much like any Red Hat Enterprise or Fedora installation. It is easy to install, works well on most hardware, and is well-behaved. Unlike Red Hat Enterprise Linux, it is free and has free updates.