James Fallow is more formal about it, writing in the Atlantic. James Fallows (July 24, 2007) – Biting the bullet on Windows Vista: back to XP (Technology)
“The other bad call came late last year, when I said that users should wait to buy new computers until the new version of Windows, Vista, was available — and that “of course” they should buy Vista-equipped machines once they could. That was wrong. I apologize.”
Thanks to Ernie for the link!