But this alternative, fan-made trailer using Mass Effect 1 and 3 elements is even better. I love the heavy emphasis on the Reapers, not just through visuals but through speech. Even the music complements it better than the one in the the official trailer.
As someone who has still yet to play Mass Effect 3 (I'm reworking through 2), another launch trailer is welcome. For those of you who have already played the game, perhaps it's a good post-mortem look, without having to look at the ending.