Liferay Portal is definitely the open source portal the most used by large companies and governments around the world.  It provides a single gateway that brings together all the informational resources and services of an organization and makes them accessible through a custom workspace in accordance to the roles assigned to each user. Liferay also includes a powerful content management system (CMS). 

Identified as a leader in the Gartner Magic Quadrant among Oracle, IBM and Microsoft, the Liferay portal distinguishes itself by its modernity. As stated by Gartner, Liferay breaks with "bloating functional and technical complexity" and traditional portals "providing faster access to value, and this without violating the norms surrounding the software."

Drupal is an open source CMS (Content Management System) that empowers millions of websites and applications ranging from personal blogs to corporate website through social networking sites, news sites, online stores, etc. An overview of the different possibilities of Drupal is available at drupalsites. Drupal is released under the GPL and developed in PHP by a community of volunteers. His modular system and its 12,000+ plugins mean that Drupal is capable of adapting to all needs and is allowing to create sites with advanced features without any development.

Pyramid (Pylons) is a lightweight web framework emphasizing flexibility and rapid development, allowing us to build custom applications integrated to your infrastructure.

It sits on re-usable open source components from the Python ecosystem, assisted by a vibrant community.

Founded in 1993, Red Hat is the leader in enterprise Linux and is the most recognized open source brand in the world. Red Hat serves global enterprises through technology and services made possible by the open source model.

Solutions include Red Hat Enterprise Linux operating platforms, sold through a subscription model, and a broad range of services: consulting, 24x7 support, Red Hat Network.

Red Hat's global training program operates in more than 60 locations worldwide and features RHCE, the global standard Linux certification.

Founded in 1975, Microsoft is the worldwide leader in software, services and computer solutions for end-users and businesses. As a Microsoft Partner, Savoir-faire Linux has access to firsthand knowledge and resources required to be effective in those computing environments.

Ubuntu is a community developed operating system that is perfect for general purpose laptops, desktops and servers. Whether you use it at home, at school or at work Ubuntu contains all the applications you'll ever need, from word processing and email applications, to web server software and programming tools. Ubuntu is the fastest growing Linux distribution.

Savoir-faire Linux provides an Ubuntu mirror in Canada : http://gpl.savoirfairelinux.net.