Quote Originally Posted by drone
The hard drive comes unformatted, so you can stick whatever you want on it.

The main advantage I see in this is that you can get a Dell without the pre-installed crapware. Even if you want to stick Windows on it, you will at least have the OS disk in hand, you can partition the drive how you want it, and otherwise have complete control of your system.
It says it doesn't include a copy of Windows...

Dell's new open-source n Series desktop solution provides customers with a DimensionTM E520, E521 or C521 desktop without an installed or included Microsoft® operating system