The GNU Operating System
The GNU Operating System, Commonly referred to as simply "The GNU System", is a complete Unix-like operating system composed entirely of free software. The creation of the GNU System is one of the goals of the GNU Project, which was launched in 1983 by Richard Stallman. It has many ambitious goals that the GNU/Hurd intends to address.
These goals include increased security through the principle of least privilege, an extensible system, conformation to open operating standards including POSIX, modularity, and respecting user freedom. Many of these goals are things that the GNU/Hurd can resolve, however the GNU/Hurd is not the most stable operating system yet.
If you are looking for a production ready GNU system, then Debian GNU/Hurd may not be the best choice for you. Debian GNU/Hurd currently lacks 64-bit support, many device drivers, sound support, SMP, and a few other essential bits that provide a flexible operating system.
However, gnu.org maintains a list of freedom respecting and production ready GNU/Linux systems. One of the most promising of these is GuixSD, which is the GNU Guix System Distribution, which eventually plans to support the GNU Hurd as the kernel!