iOS 4.2 -- has moves past the beta phase and onto GM, which means retail units should be seeing it soon. Besides the iPad, Apple is also providing builds for the second, third, and fourth generations of the iPod touch, along with the iPhone 3G, 3GS, and 4... so if you've got a friend with an iPhone Developer Program subscription, now would be a great time to get cozy.
Update: Apple made some last minute tweaks that give fast access to brightness, volume, and AirPlay controls right in the multitasking bar (pictured after the break). Apple's also on the verge of allowing MobileMe service logins using an Apple ID.
[Thanks to everyone who sent this in]