Stability
The Debian devs spent an extra five months past the planned launch date making sure that the system is as bug free as possible. Lenny will be supported for two more releases, translating into about four years of support.A Butt-load of Packages
There are somewhere in the range of 14,000 packages (miksuh corrects my number to 22,000), supposedly more than any other distribution. If you're used to Ubuntu, you'll find just about every package in Ubuntu's repositories are in Debian's, plus some.Because of the long freeze during bug fixing, though, many of these packages are behind the six-month distributions. They are actually mostly on par with Ubuntu 8.04. The highlights are:
- Kernel 2.6.26
- Gnome 2.22 (mostly -- Nautilus and the panels are from 2.20 because of gvfs problems).
- KDE 3.5.9 and 4.1
- XFCE 4.2
- LXDE 0.3.2.1
- Hildon 2.0.7 (a desktop for embedded systems)
- Xorg 7.3
- OO.o 2.4
- Firefox 3
- Apache 2.9
- MySQL 5.0.51
- PHP 5.2.6
- Ruby 1.8 and 1.9
- Python 2.5.2
- eGroupware 1.4
- Horde 3.2 (groupware platform)
- Xen and KVM
- Adobe Flash
- Some hardware firmware, especially for wireless devices.
- Non-free programs like Parallels in the Canonical Partner repository.
Many Platforms
Debian supports a huge number of architectures. In addition to the normal x86 and AMD64 arches, there is support for armel, mips, sparc, and others. Debian will run on just about anything, which is why Debian already runs on the G1 Android phone.An Easy (But Textual) Installer
Debian's installer doesn't look nearly as pretty as Ubiquity (Ubuntu's installer), but it is actually the same one present in the Ubuntu alternate install. Very few questions require any thought, and the default answers are acceptable for most normal installs.
What the textual installer gives Debian is cross-platform installability. The same installer works on all supported platforms.
As miksuh pointed out in the comments, and I completely forgot, there are other options:
- A GTK installer which has exactly the same dialogs as the text editor, and
- You can install from the Debian LiveCD project.