Another bit which may or may not make it into 2.1 is copy/paste. We're still both hopeful and skeptical, but supposedly in the new version of the WebKit framework exists commands for "plugins," "copy," "paste," "cut," and some others. We can't confirm if these really exist (and if they do, we don't know how they've actually been there, or if they're simply holdovers from the desktop WebKit frameworks), so don't hold your breath. Also supposedly making its first appearance in the 2.1 beta code: Apple's push notification service.
Oh, and by the way, if all this has whet your appetite for the device, sounds like today will be a bad day to try and snag one. Apple's retail site shows absolutely zero iPhone availability in the US, so if you're jonesing then check out eBay or the seedy looking dude on the corner with the overstuffed trenchcoat.
Update: Looks like the stores have been updated in the last hour, many have stock. Game on!
[Thanks to Cameron and everyone who sent these in]
Read - Apple all out of stock
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Read - 2.1 getting background push?