[ikonst]

Last time I checked, code signing certificates could be had for $400 a year, not an exorbitant price to many tech enthusiasts.

[rplnt]

However, being able to support the driver so it passes the certification process with every update is not something many tech enthusiasts would want to do.

[cypher543]

Certification is only required if you want to display a "Certified for Windows" logo, prevent a warning dialog from displaying on Windows XP, and/or distribute your driver through Windows Update.

[rplnt]

The warning dialogue is displayed on all versions of Windows, depending on the driver. Some can't be installed at all.