I started using Linux (Red Hat 9) on my home computer in 2003 and my first question like all Linux Newbies was: "What is a Best Desktop Linux Distribution for home users?”  Google search for this question was unsatisfactory and inconclusive and I kept stumbling around testing distributions endlessly.  After many years of playing & experimenting around with lots of Linux distributions I have come to some understanding of this question. I will put my thoughts and understanding together here about what is the best desktop Linux distribution for home users.
 
Open Source Freedom
Linux is Open Source and free for everyone .It is distributed under the GNU General Public Licese. Anyone can download, install and distribute its copies amongst their friends and colleagues. There are also commercial Linux distributions, but most of the desktop Linux distributions which a home user can use are totally free to download. Donations to a Linux distribution which one uses is a way to acknowledge the work and efforts put towards making that distribution but that’s entirely optional for the end user, nobody will ever force you to pay for their distribution that you are using. Purchasing Linux CDs from organizations like LinuxCD.org, OSDisc.com, Linux Pakistan (www.linuxpakistan.net) or Copyleft Solutions (www.copyleft.com.pk) is entirely different if they charge you. They charge you for the download bandwidth they used, for the media and postage costs.

Hardware Compatibility
A Desktop GNU/Linux Distribution can be installed on any computer with Intel x86, x86-64, AMD amd64 and PowerPC type Processor Architectures. There are many distributions which can be easily installed on older computers like Pentium II and works fine for you.  ISO files of all these processors types are separately available on the download pages of all Linux distributions.  Besides processors architectures, Linux supports almost all commonly available hardware like VGA cards, Sound cards etc.

Linux Desktops
I was sick of the monotonous looks (GUI) of Windows and wanted something different.  Linux offers KDE & GNOME as the main desktop environments amongst many others. I found KDE to be the most user-friendly in many aspects. It is simple, elegant and offers all tools which I used on windows at my home computer. So I can call it a better replacement to a Windows desktop. It offers lots of themes, fonts and wall papers selection which is what a home user likes to have. Any one amongst the family members can choose whatever type of desktop he or she likes.

Point & click ability
Most of Linux distributions these days offer graphical front end system management along with shell and it has become easier for a Linux non expert home user to use Linux without much troubles. You have controls panels, graphical package managers and hardware tweaking tools. You can connect your printer, digital camera, webcam and even watch TV on your Linux system and all these are set by few clicks. Point and click ability further extends what you can do when it comes to the installation of your Linux system on your home computer. Gone are the days when only Linux experts could install Linux distributions.  Now almost all distributions offer graphical installers and a few basic questions and selection of a partition where one wants to install the Linux system, which will take you to a properly installed Linux distribution in a short time.

Security
Life is easier for a home user of a computer in regards to security when he or she is using Linux. Linux is far more secure than windows regarding attacks of viruses, spywares and Trojans etc and offers built-in firewall and free open source antivirus like ClamAV™ if anyone is interested in installing it.

Common softwares available on a Desktop GNU/Linux distribution that a home user needs:

Internet Browsers
Firefox, SeaMonkey and Opera are available in almost all Desktop Linux distributions.

Office Suites
Open Office, KOffice, Gnome Office and Star Office.

Email clients
Firefox's Thunderbird, Evolution & KMail are the most popular Linux email clients.

Media Players
MPlayer, VLC media player, Xine - A Free Video Player, Amarok is the music player for Linux

Chat Clients
Kopete, Pidgin, aMSN, XChat, KIRC are different chat clients available on GNU/Linux Desktop Distributions.

Download Managers
If you are downloading small or large files, KGet & Downloader 4 X are good choices on a desktop Linux distributions .You have Azureus and K Torrent if you want a torrent client and emule for P2P files sharing and downloads.

Running Windows applications on Linux
Ok, so you are still Windows nostalgic and want IE, or your kid wants Windows games on Linux or your wifey wants MS Office on your Linux Desktop. Wine, Qemu, Cedega, CrossOver and VMware workstation for Linux will help you successfully achieve these tasks on your Linux Desktop.  Wine and Qemu are Open Source and can be installed on your Linux Desktop very easily and will run windows programs quite easily on your desktop computer.   Cedega, CrossOver and VMware workstation for Linux are commercial software which will help you play windows games on Linux or run Windows programs on your Desktop Linux.

The Best Desktop Distributions for Home Users.
Considering all these points I find following KDE Desktop Distributions as to be the best for home users.
1. Pardus Linux 2007.2 from Turkey http://www.pardus.org.tr/eng/
2. PCLinuxOS 2007 from the USA www.pclinuxos.com
3. ALT Linux Desktop 4.0 from Russia
4. Mandriva Linux from France

These are my personal choices of best desktop Linux distribution for home users and they can vary for others.  As for my personal choice about a desktop Linux distribution is concerned I prefer the one which makes my life easier as compared to that of problems related to windows and those with text based distributions which I think always distract away Linux non experts home users.