As I've blogged before, Windows Vista's development progress is closely aligned with Windows Server 2003 R2.
Simply put: It was from clean server code that Microsoft began earnest
Windows Vista development. I would expect Windows Vista Beta 2 (the
build that supposedly will be publicly distributed) to be available
around the same time as or soon after Windows Server 2003 R2 releases
to manufacturing. Hypothetically, assuming Microsoft releases the
public Windows Vista beta in December, development time to go from
major beta to final release would be tight to meet that late July 2006
Not that it matters. Looks to me like the big PC upgrade cycle is occurring now and that Windows Vista will have missed the opportune launch window.
And, if that's the case, would an even later release but one better
built make more sense? Maybe if you worry wart Windows release dates [Microsoft Monitor]