It's totally September 11th-
1) That's a Tuesday
2) Apple has been grouping iPod announcements together in the past few years, more and more so. Now they are completely together, and announced in early September. (Yes, three years or so of data, but hey that's all that should count).
3) Plus, October will be devoted to Leopard; build up is an important process for marketing (etc.) and can't have enough time if iPods are released too late in September. (We know they won't be released just before Thanksgiving, as there needs to be ample time to get on wish lists and shoppers' awareness).
Say Leopard is released Friday, October 26. That requires at least two weeks of official announcement time, and two weeks of rumors / potential build up. iPods need to have their moment in the spotlight over by the time the 4-week "Leopard period" begins. Say several weeks after iPods are announced, and that pinpoints the 11th as a likely launch date.
-=|Mgkwho