Indeed if you start googling you can see that most places say that removing the heatsink improves the drive. Apart from making it "smaller", it produces alot less noise. The "heatsink" actually generates alot of noise and doesn't cause the temperature to drop.
I suppose it does look cool, but at the cost of noise is stupid. WD should have never put in the heatsink in the first place. Unnecessary waste of resources.
http://www.silentpcreview.com/article844-page1.html
Suppose WD should be congratulated on reducing some of the unnecessary waste with their products tho... maybe HP could take a leaf out of their book :)