Newly recruited Bungie.net reporter Mnemesis has written up a report in the HBO forum from the HNC Finals... where the Halo 2 Trailer was shown.
While the trailer itself has been written about numerous times already, he does add a few impressions of his own:
The Earth is shown both directly and in the background, and I can say for sure that Earth is definitely being glassed. Huge shockwaves repeatedly burst on the surface. Aside from the lighting, which has been drooled over already, there is a depth-of-field focus element to the game that looks absolutely awesome.
Alas, there's no shaky, low-quality handycam footage; his camera's batteries were charging while the trailer was playing. So, back to your regularly scheduled hurry up and wait for four more days...