For users of ordinary Linux distros (such as Slackware or Fedora) it may be difficult to understand how extraordinary and multifarious project Debian actually is. Debian GNU/Linux supports more hardware architectures than any other Linux distro. Also, Debian is not tied to Linux alone - Debian supports many other kernels, such as BSDs, Hurd, etc.
In Debian GNU/Linux you have several 'distros' bundled together -- you can use Debian Stable as a rock solid server, Debian Testing is a reliable workstation solution and Debian Unstable offers the cutting edge desktop software. There are also several techniques available for you to build your own mixture of Stable, Testing and Unstable.
Because Debian is free and maintained by a community of volunteers, Debian is independent of commercial success or the whims of individual developers. Some other distros may cease to exist if they go bankrupt or their lead developer decides to quit but you can always rely that Debian will be there for you also tomorrow.
That being said, you should try different distros and choose the one you feel most comfortable with. Linux, because it is Open Source, is good platform for developing software.