This new version of Debian includes various interesting features such as multiarch support, several specific tools to deploy private clouds, an improved installer, and a complete set of multimedia codecs and front-ends which remove the need for third-party repositories.
Multiarch support, one of the main release goals for "Wheezy", will allow Debian users to install packages from multiple architectures on the same machine. This means that you can now, for the first time, install both 32- and 64-bit software on the same machine and have all the relevant dependencies correctly resolved, automatically.
The installation process has been greatly improved: Debian can now be installed using software speech, above all by visually impaired people who do not use a Braille device. Thanks to the combined efforts of a huge number of translators, the installation system is available in 73 languages, and more than a dozen of them are available for speech synthesis too.
In addition, for the first time, Debian supports installation and booting using UEFI for new 64-bit PCs (amd64), although there is no support for "Secure Boot" yet. This release includes numerous updated software packages.

About Debian

The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system is called Debian GNU/Linux, or simply Debian for short. Debian systems currently use the Linux kernel. Linux is a completely free piece of software started by Linus Torvalds and supported by thousands of programmers worldwide. Of course, the thing that people want is application software: programs to help them get what they want to do done, from editing documents to running a business to playing games to writing more software. Debian comes with over 20,000 packages (precompiled software that is bundled up in a nice format for easy installation on your machine) - all of it free. It's a bit like a tower. At the base is the kernel. On top of that are all the basic tools. Next is all the software that you run on the computer. At the top of the tower is Debian -- carefully organizing and fitting everything so it all works together.