So this is mostly the same trailer as what was seen at E3, however the end shows something new, and awesome.

Holy crap, the Chief looks amazing, this is a whole step up from the Reach stuff we saw, I can't freaking wait to see the full length Videos that these are teasing, a full hour and a half of this awesomeness!

http://www.youtube.com/watch?feature=player_embedded&v=yx2kbROpxP8

I really love all the other live action shorts/commercials they've done for the last games, but this seems to be on a whole other level, looks awesome.

That's really cool for me. Cannot wait.