Three realistic human eyes (brown, blue, green) to use for your characters as I often see very good head models and really poor eyes that kill the quality and literally suck out the life of your model.
The eye Object has a custom property to animate and control the pupil aperture.
The eyes should also be downward compatible, you can still use the shapekeys to animate the pupil aperture, just the driver will now work in non 2.5 versions.
The textures and the texture template for GIMP are also available, you can download them in the Blender Artists Forum thread here where you also find more information and also video previews:
You can also download the GIMP file here: