Full two and a half minute 2nd trailer, to say it looks intriguing is an understatement. Looks like someone's been watching Werner Herzog's Cave of Forgotten Dreams for some inspiration here.

http://www.youtube.com/watch?v=pCtvg6rU … ata_player
Certainly a lot to think about in this trailer, hope it is the last one though. This one gives hints on the plot, but still manages not to give too much away. I feel revealing any more would possibly spoil it.
So what do we have here? Ancient scrawlings on a cave wall which lead the way to first contact with aliens, who at first seem benevolent, but something happens once they get there that makes them seem anything but. They were so wrong. Then we get live Space Jockey action, and possibly the first exposure to alien bio tech which could lead to the development of the Alien as we know and love it. Not to mention the beginning of The Company's obsession with getting their mitts on that tech at any cost judging by how mental Michael Fassbender's android looks in some of those scenes. June can't come soon enough.
There is an issue with the look of the level of tech in this movie which looks more advanced than what we've seen in Alien and Aliens. An analogy which I thought was apt was that the vessels of Alien and Aliens were well used old workhorses of industry and the military, so the equivalent of an old truck and a Humvee, where as the Prometheus being a state of the art science vessel of it's time is more like a Ferrari. So even though it is 30/100 years older it still looks sexier and more sophisticated. That's one way to look at it anyway.