Fallout: New Vegas - Preview @ CVG

CVG reprints a Fallout: New Vegas E3 preview from XboxWorld360 magazine.  Here's a snippet on the faction system:

Once into the central control room you have a number of options that will either cement your relationship with the NCR, or damage it. We go for damage. Big damage. Our man reroutes the power to an orbital laser, which he then uses to incinerate the NCR troops stationed outside the power plant. It's spectacular as the giant beam sweeps over the baked floor, evaporating the opposition. Later on in the game, we're told, that orbital laser can become part of your arsenal as you develop a portable control device for it. Like the Hammer of Dawn from Gears of War, only far more powerful.

Attacks on specific factions will have much more subtle, believable consequences. In fact, everything you do will matter more thanks to a combined reputation and morality system. Our little atrocity will probably evoke retribution from the NCR, but because it was a significant attack on their rivals, Caesar's Legion might sit up and take notice. Morality is more than just good and evil here. There are many grey areas and because morality is tied into your reputation, it's possible to be hated in some parts of the world and revered in others. Even seemingly 'goody-goody' choices will have bad consequences for some.