If you are interested in checking out BSD as a desktop OS alternative, but the installation and setup seems a bit much for you, check out
PC-BSD. PC-BSD is also a great alternative for those looking to get into UNIX and wanting an alternative to the Linux distributions.
PC-BSD has as its goal to be an easy to install and use desktop OS, which is built on the FreeBSD operating system. To accomplish this, it currently has a graphical installation, which will enable even UNIX novices to easily install and getup and running. The system comes loaded with the "K" Desktop Environment (KDE), which lets users immediately sit down to a familiar interface. Also developed exclusively for PC-BSD is the PBI system, which lets users download and install their applications in a self-extracting & installing format, similar to InstallShield® on Windows®.
I am by no means a BSD expert, I have installed and used FreeBSD and thought it a very stable and impressive OS. With a little reading and searching I had a nice little desktop system setup using a very modest PC. But I have to say, it does not get any easier than PC-BSD. It is as easy a setup as any operating system I have ever installed and the package management system is very impressive.
