Mandrake

Uses the Redhat Package Management(RPM) system for installing programs.
Comes with all the major window managers(KDE, GNOME, WindowMaker, etc.).
Comes with the DiskDrake hard disk partitioning program.
If you have multiple operating systems running, you will have access to your MS Windows partitions from within Mandrake at the end of the installation.
Set the security level during the installation.
 

Red Hat 6.2

Version of choice for Faculty Support.
First came out in the summer of 1994.
Redhat appears to be the biggest and best known company of the major distributors.
Runs on Intel/AMD, SPARC, and Alpha processors.
Installation by CD, HTTP, FTP, NFS, and a local copy on your hard drive.
As part of the installation you re-partition your drive for the distribution, but this is not required.
Fully customizable installation, choose one of the pre-selected options, or customize right down to each individual program you want installed.
Does not run on top of Win9x/NT, must install the bootloader(LILO) if you intend to have multiple OS's installed.
Recognizes ATAPI Zip and Jaz drives.
Comes with the GNOME and KDE window managers.
New feature with 6.2 detects any hardware changes on boot.

Calera Open Linux 2.3

Strongest competitor for Redhat
Installation includes LIZARD(Linux Wizard), a graphical installation that detects most hardware by itself.
Comes with KDE, Full-featured demo of Applixware office suite, Star Office 5.1, Corel Word Perfect 8.
Also includes special versions of PQMagic and Boot Magic(Complete versions are site licensed at the UW).

Corel

This one just burst onto the scene in November 1999.
3 core versions: Download, Standard, Deluxe
Based on Debian's distribution(see below)
Detects hardware during installation.
Special Corel user interface, based on KDE

Debian 2.1

This distribution is maintained strictly by volunteers.
Highly customizable, you select what you install.
Available on CD for only $5.
 

Slackware

Claims to include "the best of all worlds" and to be the most Unix-like of the major Linux distributions.
Works on everything from the Intel 386 on up.
Comes with all the major software.
2 other options: ZipSlack and BigSlack.
ZipSlack allows you to install Slackware on a single 100M Zip disk and run it from any Zip drive.
BigSlack allows you to install Slackware in 800M of an existing Windows partition

Suse

Automatic detection and configuration of major hardware and your Internet connection.
Comes with an quick setup and installation guide with screenshots of every step.
Comes with all the major programs, plus video editing software and a 3D drawing program.
Cost is about $50, not available for free.

Winlinux

Installs directly on top of an existing MS Windows operating system.
Supported hardware is automatically detected and configured based on your existing MS Windows configuration.
Double-click to start from within MS Windows, in most situations.
No special partitioning.