The rumor had been RTM on the 8th, but Paul Thurrott has an exclusive tip that it may now be the 6th:
In its quest to finalize Windows Vista, Microsoft has faced two hurdles in recent days, one technical and one a bit more unusual. The proposed final build was marred by a few late breaking bugs, which the company expects to squash over the weekend. Meanwhile, a power outage in the Windows build lab Friday night prevented Microsoft from creating a new Vista build that night.
Expect availability to OEMs, businesses with volume purchase agreements, and MSDN subscribers to follow in very short order as there’s no point in delaying until the November 30 USA launch event (Nov. 23 in Canada).