I've only been to the flagship store on Fifth Avenue today, so I'm not in a position to generalize.
But shortly before 8 a.m., when the store usually opens for a new launch, I had a headcount of 550. According to the records Piper Jaffray's Gene Munster has been keeping since 2008 (see below), that's more customers than turned out for the iPhone 3G, iPhone 3GS and iPhone 4S.
And by 9:56 a.m. -- four minutes before the doors finally opened -- I counted 801 men, women and children. Only the iPhone 4 (1,300) and iPad 2 (1,190) drew bigger crowds.
Below: Piper Jaffray's iPad and iPhone headcounts. Munster's count of 580 for the iPad mini looks like an 8 a.m. tally. He estimates that Apple will sell 1 to 1.5 million iPad minis before the weekend is over.