Unlike the iPhone and iPod touch, the iPod nano doesn't have an accelerometer to determine orientation. That's a good thing--you can clip the device in any orientation you want, and then use two fingers to "spin" the iPod's interface so that it's displaying face-up for you.
No, this iPod nano isn't like an iPhone, with downloadable apps and the like. And it's utterly lost the ability to record or even display video--"nano does video" no more. You can display photos on the tiny 1.5-inch touchscreen, and they look nice, but they are most definitely small.
One last detail: Unlike the iPod shuffle, which requires a special cable that plugs into its headphone jack in order to sync with a Mac, this tiny nano still has a full-sized iPhone dock connector port.
Fourth-generation iPod touch
The new iPod touch is, internally, very close to being an iPhone 4. It's got the same Retina display, and it's got forward and backward facing cameras (though the rear camera shoots at 960 by 720 resolution, much less than the iPhone 4's) and support for FaceTime video chat. But it's got some clear physical differences, too, most notably its thinness. The last generation of iPod touch was already thin, but it's even thinner now, and quite light. The screen looks great.
There's a new FaceTime app, which you use to initiate FaceTime calls. (To answer the question, how does a device that's not a phone receive FaceTime calls: It does it via e-mail address. You enter e-mail addresses in the FaceTime settings, and then people can call you and you can call them via the FaceTime app or the Contacts app.) And yes, there's a microphone on this iPod touch so you don't have to put on headphones to use FaceTime: It's located on the bottom edge of the device.
Beyond that, I'm not sure what we can say about the iPod touch. It's the thin, small iPod touch we've come to expect, but loaded with many (though not all) of the iPhone 4's features. If you were drooling over the Retina display but didn't want to buy an iPhone 4, now you don't have to.
Second-generation Apple TV
The Apple TV was released four years ago, and even with an updated interface, added features, and price cuts, it was never what we'd call a success. Part of that can be attributed to the fact that Apple considered it a 'hobby' and never really devoted the time or resources to make it a better product, but as Steve Jobs admitted during today's event, it also didn't give customers what they wanted.