Environments

Your desktop environment is entirely a matter of preference. You can't argue user preference. While it is a great source of fanboy debate, the truth is that all desktop environments have their strengths and weaknesses. Choose the one that's right for you. Most distribution come with a default desktop environment, while a few let you choose during install which one you'd like to use. You can always switch later but it's not always as smooth a process when you switch.

Here are the most well known desktop environments:

GNOME
"The GNOME desktop environment, is a free, intuitive and attractive desktop for users. GNOME is Free Software and part of the GNU project, dedicated to giving users and developers the ultimate level of control over their desktops, their software, and their data.
GNOME understands that usability is about creating software that is easy for everyone to use, not about piling on features. GNOME's community of professional and volunteer usability experts have created Free Software's first and only Human Interface Guidelines, and all core GNOME software is adopting these principles. GNOME is used, developed and documented in dozens of languages, and we strive to ensure that every piece of GNOME software can be translated into all languages. Beyond the worldwide GNOME Community, GNOME is supported by the leading companies in GNU/Linux and Unix, including HP, IBM, Mandriva, Novell, Red Hat, and Sun".
website: www.gnome.org


KDE
"KDE is an international technology team that creates Free Software for desktop and portable computing. Among KDE's products are a modern desktop system for Linux and UNIX platforms, comprehensive office productivity and groupware suites and hundreds of software titles in many categories including Internet and web applications, multimedia, entertainment, educational, graphics and software development. KDE software is translated into more than 60 languages and is built with ease of use and modern accessibility principles in mind. "
website: www.kde.org





XFCE
"Xfce is a lightweight desktop environment for various *NIX systems. Designed for productivity, it loads and executes applications fast, while conserving system resources." - Olivier Fourdan, creator of Xfce

Xfce 4.6 embodies the traditional UNIX philosophy of modularity and re-usability. It consists of a number of components that together provide the full functionality of the desktop environment. They are packaged separately and you can pick and choose from the available packages to create the best personal working environment.
website: www.xfce.org



LXDE
The "Lightweight X11 Desktop Environment" is an extremely fast-performing and energy-saving desktop environment. Maintained by an international community of developers, it comes with a beautiful interface, multi-language support, standard keyboard short cuts and additional features like tabbed file browsing. LXDE uses less CPU and less RAM than other environments. It is especially designed for cloud computers with low hardware specifications, such as, netbooks, mobile devices (e.g. MIDs) or older computers. LXDE can be installed with distributions like Ubuntu or Debian. It provides a fast desktop experience; connecting easily with applications in the cloud. LXDE supports a wealth of programs that can be installed locally with Linux systems. The source code of LXDE is licensed partly under the terms of the the General Public License and partly under the LGPL.
website: www.lxde.org