ComingSoon has added some more information about the Deathly Hallows preview that was shown at ShoWest; read more here & here. Spoilers:

The footage opened with Ralph Fiennes as Voldemort in a clearing followed closely by his Death Eaters. Being unfinished footage, Fiennes still had dots on his face and there were placement dots for later FX, but soon, they meet up with Harry Potter and Voldemort snarls, “Harry Potter… Come to die.”

That sets up the footage which makes it clear that the last two movies are going to be about the final showdown between the two long-time nemeses, and much of what we saw involved Voldemort plotting with his Death Eaters how he was going to capture Harry Potter and how he wants to be the one to kill him when they do.

The Ministry of Magic is clearly falling apart and they seem to be after our heroes as well, but as someone who hasn’t read the book, it wasn’t clear whether the Ministry were working with Voldemort to catch Harry or whether they had their own agenda. One scene shows multiple Harry Potters, and we see a bit of Bill Nighy as Rufus Scrimgeour, looking very fierce, as well as quite a lot of Helena Bonham Carter’s Bellatrix Lestrange acting suitably crazy as she interacts with the kids after they’ve been captured and are being brought to the Death Eaters safe house.

There was some footage of the trio running through the Forbidden Forest being chased by something, a quick anamatic of the giants smashing up some building (Hogwarts?) with their clubs, and footage of the kids being chased by a dragon. Another unfinished scene showed Hagrid on a flying motorbike that was rocketing through the side alongside what looked like Hermione and other Hogwarts denizens on broomsticks, as well as others riding Thestrals (those flying horses), seemingly being chased by a flying Voldemort or another Death Eater. With all of this happening, the friendship is also having trouble withstanding all of the strain, and in one scene, we see Harry and Ron really going at it, even more than we’ve seen them arguing in the past.

The footage ended with what might be the final confrontation with Voldemort as he asks Harry, “Why do you still live?” to which he gets the response, “Because I have something to live for.”