Well, IIRC there are two right now. Tactical and Explosive. Tactical is an extra weapon, Explosive is an extra mission that splices into the main story line. Missing Link isn't supposed to be out until sometime this month.
So, I'd suggest
In that order.
This one? http://www.deusex.com/humandefiance
Or this one? http://www.pcgamer.com/eidos-introduce-the-engine-behind-the-upcoming-deus-ex/ (The latter only shows the new engine, not an image from the new game.)
This looks alright I guess. What I would really love to see is a Deus Ex movie based on the video game, but they would probably just hire Uwe Boll and ruin it like they always do.
September 8th on the calendar is empty, but active, probably as a placeholder for such an announcement (then again, there is the sunday thing on the "missing link" picture. we'll have to wait and see. )
Those aren't in the augmented edition. They're pre-order bonuses.
Of course the pre-order mission is Tong's Rescue, which I'll probably miss out on then. Thanks pre-order bonuses; you always know how to make me feel left out.