mistermumbles: Trailers are nice, but they usually don't do it for me. Browsing YouTube quickly for some actual gameplay videos is typically easier and gives me a better idea of what a game may be like.
Wishbone: I'll say it depends very much on the trailer. Cinematic trailers are completely useless, but some trailers are very good indeed. But yes, it's generally a good idea to watch a gameplay video as well.
I don't think Cinematic trailers are always necessarily completely useless (just most of the time), sometimes they can actually set the scene for the style of game. But I certainly agree most cinematic trailers aren't representative of the actual game.
The Omikron trailer was pretty good to my tastes, the setting looks cool, the song was good (by David Bowie, even!) and apparently it's a Quantic Dream game made by David Cage. (Which makes me somewhat hopeful, I loved Indigo prophecy[Fahrenheit] and hated Heavy Rain)