Just to reiterate a couple points, while you can connect any DisplayPort 1.1a compliant display to a Thunderbolt host controller, Apple is pretty clear that the ATD must be connected to a Thunderbolt port, which makes sense when you think about it.
Thunderbolt does support bus powered devices, but the ATD requires way more than the bus can provide, and thus A/C powerdespite the lack of power cords in the glamour shots.
As for USB 3.0 being left out, some back of the envelope calculations show that the ATD with just the connections it does provide could utilize 84% of the 10 Gbps available on one Thunderbolt channel. The video signal alone requires at least 5.8 Gbps, so there wouldn't be much room to breathe if you added USB 3.0 to that pipe as well. A single USB 3.0 host controller is able to pump the better part of 5 Gbps by itself. When they eventually hit the market, you could always add a Thunderbolt to 4 port USB 3.0 adapter, which would be fine because it would utilize the second TB channel.
The complaints about the price of this device are insane when you add up the cost of the individual components in it. First we have the 27" 2560x1440 IPS display and Thunderbolt controller. Then we have a 1280x720 video camera with microphone, no biggie. Then a 2.1 speaker system with a 49 watt amp. Marinate on that oneshow me another display with a built in amp anywhere near 49 watts. Then we have 3 powered USB 2.0 ports, a FireWire 800 port and a Gigabit Ethernet port. These are not pass through ports pulled off of an attached computer, they all have their own host controllers and are hooked to the Thunderbolt controller via PCIe. And don't forget the MagSafe charger and Thunderbolt cable that come attached to the ATD. Go ahead and add up how much it would cost to buy all these things separately and get back to me.
For all y'all bitching at Apple for the steps backwards from the 30" ACD, I think the blame really has to be directed at least in part at the panel manufacturers. With the much broader consumer electronics market (televisions) demanding cheap 16:9 displays, that's exactly where they focused. The vast majority of displays on the market today, regardless of size, top out at 1920x1080. I'm pretty sure that's also why you don't see Apple making a smaller version of the ATD. There's nothing under 27" at greater than 1920x1080 and the competition in the 1920x1080 market is brutal. Who needs yet another 1920x1080 display?
For those trying to connect multiple monitors without Thunderbolt, there are several DisplayPort to 3 DVI port adapters available. So you can hook 2 or 3 DVI-D enabled displays to a Mac or PC with a single DP/MiniDP/TB port.
http://i.dell.com/images/global/products/monitors/mmh11.pdf
The polished glass in front of Apple displays is just integral to the current design language. There is no way to make these devices look as attractive and seamless as they do without the full frontal glass. I recommended applying an anti-glare film, and someone quickly responded that they had tried these and that they made the screen look worse. You can imagine that Apple tried a lot of things, and in the end this was the best they could come up with. What then, is the best panel on the market with a matte finish, and does it have any glass in front of it at all? I'm pretty sure the glass adds considerably to the durability of these displays and not just to the amount of glare they produce.