When considering the installation of a new operating system, the first thing to do, obviously, is to pick one. With Windows or Mac OS X, it's a fairly simple choice. Consumers are usually forced into one or the other, depending on whether you're buying a PC or a Mac. Times are changing, though -- it's possible to install Windows on a Mac now that they're using Intel processors, and some manufacturers (notably Dell) are offering Linux installations on select PCs.
With free operating systems, the decision is a bit more complex. There are plenty out there, but the most popular are BSD and Linux. Both of these are Unix-like systems, and while there are some differences, they would likely pass unnoticed by the average user. Each can be installed on both PCs and Macs. BSD is a fairly direct descendant of the original Unix, and its development has been fairly structured. The development of Linux, on the other hand, has been a bit more... organic. It could be said that BSD was engineered but Linux was grown. Neither is necessarily better than the other, though there are plenty of people on both sides who would vehemently disagree.
There are three freely available versions of BSD. FreeBSD focuses on efficiency and reliability, NetBSD focuses on portability (i.e. being able to run on any machine, from your laptop to your Playstation), and OpenBSD is (ironically) obsessed with security. Unless you're concerned that government satellites might be reading your thoughts (in which case you fit right in with the OpenBSD crowd), FreeBSD is probably the best of the three for a desktop operating system, though like its siblings it's really targeted at servers.
Linux is a completely different beast altogether. There are about three hundred different flavors (called distributions) of Linux, though the core of the operating system itself (i.e. the kernel) is essentially the same from one to the next. The primary differences between distributions are the software bundled with the operating system and the community of users and developers that supports that particular distribution.
Linux, in my opinion, is the better choice of operating system for the average PC user for a couple of reasons (other than it's cool mascot, Tux). First, Linux tends to have slightly better support for the more PC-specific hardware like webcams and WLAN cards. Second, Linux is significantly more popular (by several orders of magnitude) with PC users. While "because everyone else is doing it" is usually a poor excuse to do something, there are times when it's a good thing. A larger user base and development community means that any problems with the system will tend to be identified (and ideally corrected) that much more quickly. By far the most popular distribution of Linux for PCs is called Ubuntu. Ubuntu has a huge user base, as well as a regular release schedule.
Ubuntu itself actually has a few variants, the most significant being Kubuntu. The difference between the two involves the last decision that needs to be made when installing a Unix-like operating system: which desktop environment to use.
Unlike Windows and Mac OS X, Unix-like operating systems are not inherently graphical. To get the attractive and convenient windowed interface with which we've all become familiar, BSD, Linux, and their relatives need to run desktop environment software. This is actually a good thing, because it gives the user greater flexibility in altering the computer's interface with a minimum of effort or difficulty.
The two main desktop environments are GNOME (pronounced "Guh-nome") and KDE. The difference between Ubuntu and Kubuntu is that the former is packaged with GNOME and the latter with KDE. Its possible to change desktop environments after installation, or even to install both and switch back and forth between the two. Each has software written specifically for that desktop environment, but again, it's possible to run such software while using the other desktop environment. You'll take a very slight hit in performance, especially when starting the software, but this might not be very noticeable given the power and speed of modern computers. While there are quite a few differences between GNOME and KDE, for the time being let's just say that GNOME is a bit like a cross between Windows XP and Mac OS X, and KDE is more like Windows XP or Vista. Both, however, are much more customizable than Windows or Mac OS X, and can be configured to look and (for the most part) act like either.
The most recent version of Ubuntu family is 7.10, "Gutsy Gibbon". Both Ubuntu and Kubuntu conveniently provide installation disks (free of charge, of course), either through the mail or by download, which allow you to test each operating system before you commit to an installation. I tried each on my old laptop, and found no hardware incompatibilities or other problems. While I like quite a few of the applications written for KDE, Ubuntu Gutsy Gibbon feels slightly more polished and complete than Kubuntu Gutsy Gibbon, so I'll be discussing an Ubuntu installation for the rest of this series.
Stay tuned for the play-by-play commentary, with pictures (and maybe even videos)!
Next time: Avoiding the "Windows Tax"