Apparently Western Digital's Marketing department and their technical support department are not on the same page.
As of Today THESE DRIVES ONLY HAVE A THREE YEAR WARRANTY!
I also purchased 2 WD4000YR and accourding to Western Digitals Warranty checker my Warranty expires on 11/15/2008!
Its not just me, someone posted the same problem on 12/03/2005, and I checked his serial number and his waranty coverage is still 11/9/2008.
The controlling legal language is irrelevant, if my drive dies on 11/16/2008 and WD's support system still says my warranty expires on 11/15/2008 then I am not getting a replacement.
Yes its false advertising & break of contract and all that, but since the US doesn't have any real consumer protection laws, my only recourse would be to spend thousands of dollars on a lawsuit.
The controlling legal language is on WDC's website (since July 18, 2005):
If there is ever a dispute over warranty coverage, the terms of that document controls the outcome, regardless of whatever some RMA tech or warranty registration system reports. The terms cannot be changed retroactively (at least for consumers in the US); any changes will only affect drives sold after the effective date of the revisions.