Fedora
The goal of The Fedora Project is to work with the Linux community to build a complete, general purpose operating system exclusively from open source software. Fedora Core is built to provide choice. It includes the latest versions of many software packages, including both GNOME and KDE desktop environments. Fedora Extras, a repository built entirely by volunteers, provides thousands more packages, and is enabled for use by default.
(This distribution also has a “Live CD” you can use to test the distribution before you install it)
OpenSuSE
The openSUSE project is a community program sponsored by Novell. Promoting the use of Linux everywhere, this program provides free, easy access to the world’s most usable Linux distribution, SUSE Linux. OpenSUSE delivers everything that Linux developers and enthusiasts need to get started with Linux. Hosted at opensuse.org, the project features easy access to builds and releases. It also offers extensive community development programs for open access to the development process used to create SUSE Linux.
(This distribution also has a “Live CD” you can use to test the distribution before you install it)
Mandriva
Mandriva Linux (formerly known as Mandrake Linux) was created in 1998 with the goal of making Linux easier to use for everyone. Mandriva offers all the power and stability of Linux to both individuals and professional users in an easy-to-use and pleasant environment.
(This distribution also has a “Live CD” you can use to test the distribution before you install it)
Debian
Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. Debian GNU/Linux provides more than a pure OS: it comes with over 15490 packages, precompiled software bundled up in a nice format for easy installation on your machine.
Ubuntu
Ubuntu is a free, open source operating system that starts with the breadth of Debian and adds regular releases (every six months), a clear focus on the user and usability (it should “Just Work”, TM) and a commitment to security updates with 18 months of support for every release. Ubuntu ships with the latest Gnome release as well as a selection of server and desktop software that makes for a comfortable desktop experience off a single installation CD.
(This distribution also has a “Live CD” you can use to test the distribution before you install it)