Well, first of all, let me bring to your attention the newest, and most likely the last, trailer for Mass Effect 3; the live action "Fight" trailer.
I've seen a lot of good live action trailers, the "We Are ODST" and "Deliver Hope trailers from the Halo promotional machine, as well as the live action Skyrim trailer from last year. This one is definitely one of the good ones.[link]
Short, but sweet.
Now, as to this next thing, I honestly didn't know how to react when it landed on my desk.
Picture it; a Mass Effect 3 comic released from --what I hear to be-- a legitimate source in Japan outlining the basics of the Mass Effect series and Mass Effect 3, focusing on Tali and Liara as schoolgirls at the "Citadel High School".
I kid you not. And before you ask; no, tentacles are not involved in any way.
Here's the translated version:(Note: this is in manga format, so you read the speech bubbles from right to left.)[link]
This is not meant to be taken seriously in any way shape or form. It's supposed to be funny, which it is, frankly. Still...
One of my friends summed it up nicely "[It's] funny, mostly because of the absurdity of it."
The reason I like this new trailer so much is that it evokes the same feelings as "Nearer My God To Thee", a fan fic I read not long after the release of the ME3 teaser. [link]
Very concise and emotional, cutting to the base of what ME3 is about, in a way.