I am starting this article here to make it very simple for those looking to put the correct working drivers on their Linux installation.

RedHat And Fedora Core

Fedora Core 4 and Above

Fedora Core 4 and later have default access to the "Fedora Extras" packages, which are hosted at www.livna.org. Users of Fedora Core 3 and older have to take an extra step to access the Fedora Extras, but it is entirely worth it.

This site hosts the sole place you need to go to get your GLX/OpenGL drivers for both ATI and nVidia GPUs under Fedora Core.

Follow the steps on the Livna Site to set up your Yum system for Livna access, and then it is as simple as the following yum commands:

yum install nvidia-kmod

or for ATI,

yum install fglrx-kmod

That's it. Reboot your X Server or PC, and you're golden. It's that simple.

See the Livna page on the subject:
Why switch to Livna ATI & Nvidia RPMS?

Ubuntu Linux

All the information you need is on the Ubuntu Wiki's page for Binary Drivers.

Gentoo Linux

NVidia

On all Gentoo's you can install your drivers by running the following:

emerge -va nvidia-kernel nvidia-glx

or to get the latest (and maybe unstable) drivers:

ACCEPT_KEYWORDS="~x86" emerge -va nvidia-kernel nvidia-glx

ATi

On all Gentoo's you can install your drivers by running the following:

emerge -va ati-drivers ati-drivers-extra

or to get the latest (and maybe unstable) drivers:

ACCEPT_KEYWORDS="~x86" emerge -va ati-drivers ati-drivers-extra

You can also use the DRI-drivers for Radeons up to r200 (Radeon 9000):

echo "media-libs/mesa ati" >> /etc/portage/packages.use
 emerge -va media-libs/mesa