[Shadowfax Clawson]

I seem to remember Tolkien writing something to the effect of Gollum's skin being pale and tallow, such as many creatures who make their homes in caves. I found they portrayal in the movie of his eyes to be the best thing about him; pale, malicious, and ghostly grey. However, I always have imagined him with pale skin, characteristic of cave creatures, with any pigment leached over the 500 years he made his home in the Misty Mountains.

Great question, Wormtongue!