According to this article on the AppleInsider website, Apple has publicly acknowledged that the forthcoming iPad will launch at the Apple retail stores and direct (online) retail outlets. During the Goldman Sachs tech conference, Apple's Tim Cook was quoted as saying, "...Initially it will be around places with really great assisted sales," Cook also said that "...over time it will expand."
For those that may not know, the "assisted sales" channel for Apple includes partners like Best Buy, which Tim did mention by name. AT&T is also considered an "assisted sales" channel (jokes about AT&T's customer service aside) but Tim did not mention AT&T by name like he did Best Buy.
The iPhoneWriter.com team is willing to bet that AT&T is definitely on the list and will happily be selling iPad's come launch day. In a manner likely similar to the launch of the iPhone, one would expect the largest available inventories to be at the Apple retail stores, leaving "assisted sales" outlets like Best Buy and AT&T having fewer available. Business logic says there should also be an element of sales volume considered too.
So, where will you be standing in line? Your local Apple retail store? Best Buy? AT&T?