The EXT4 file system has been made the default file system in Debian 7.0 as compared to EXT3 which was used up until now. You are still free to set the file system as per your choice but, this feature is significant as other distributions had already made the move away from EXT3 as default file system and Debian has done that years later.
Debian 7.0 now includes support for different desktops namely GNOME 3.4, KDE 4.8, and Xfce 4.8.
With Wheezy, Debian now supports a total of 9 different architectures allowing users to install the distro on systems ranging from handheld computers to even supercomputers. These architectures are 32-bit PC / Intel IA-32 (i386), 64-bit PC / Intel EM64T / x86-64 (amd64), Motorola/IBM PowerPC (powerpc), Sun/Oracle SPARC (sparc), MIPS (mips (big-endian) and mipsel (little-endian)), Intel Itanium (ia64), IBM S/390 (31-bit s390 and 64-bit s390x), and ARM EABI.
Debian 7.0 installer includes support for UEFI installations on both x86 and x64 hardware. Visually impaired users who do not use a Braille device will now be able to install the distro using software speech. The installer is available in 73 languages with over a dozen of them being available for speech synthesis. Support for WPA/WPA2 wireless has also been included in the installer.
Some of the other features are: Systemd is now available in Debian as an option; FFmpeg being replaced by libav media project fork; new server options for Debiain server now includes OpenStack and Xen Cloud Platforms; real-time (RT) kernel options if users install linux-image-rt-amd64 or linux-image-rt-686-pae kernel packages.