Take it from us, your London-based sleuths, when anything sells faster than Harry Potter books or DVDs in the UK, it's scorching hot. Case in point is Microsoft's Vista successor, which has sold so well that it has beaten the Amazon UK pre-order record previously held by J.K. Rowling's Harry Potter and the Deathly Hallows. In fact, Windows 7 was able to tally up more sales in the first 8 hours of pre-order availability than Vista was able to collect altogether. Now that's what we call an upgrade.
http://www.engadget.com/2009/10/21/windows-7-breaks-amazon-uk-pre-order-volume-record-ousts-harry/