We've learned a bunch more information about Fallout: New Vegas from the PSM3 article. Check out the list below:
It shows the command wheel for followers, with 8 commands: toggle melee/ranged, open inventory, toggle stay close/keep distance, back up, toggle aggressive/passive AI, use stimpack, toggle wait here/follow me, return to normal dialogue.
Scripting is wittier, characters more distinct. Example from vigour test word association: mother-human shield.
Opening inventory consists of a kit from the doc, adapted to your starting stats (like Fallout 1).
The Nevada area is less affected by the nuclear war, so it has plant life, relatively unspoiled houses, and in visual presentation has saturated colours and a bright sky.
There's a tutorial (led by a character named Sunny who looks a lot like Moira Brown), but unlike Fallout 3, it's optional, so you can hit the open game in 5 minutes from starting.
NCR and Caesar's Legion are the confirmed faction, article assumes Brotherhood of Steel will be in but they weren't not mentioned in the presentation.
"In New Vegas it's all about the player examining the ideologies of the various groups that are controlling the area and supporting one over the others," explains Sawyer. "Each of the ideologies will have something good that you can relate to, but will also have massive flaws."
When asked about PS3's Fallout 3 being inferior to the others and if New Vegas will do better, Obsidian devs make no promises but indicate it was a learning process and they're working with all 3 platforms and all have problems.
The New Vegas strip is still in construction but will have gambling, variety shows and concerts.
Electrical power is key in the faction struggle.
Radiation is still a problem, there's a nuclear test site to explore north of New Vegas.
The soundtrack will blend "Rat Pack style tunes with more Western numbers".
New Vegas doesn't tell a single-player story, but weaves decision into the gameworld and gives you greater power to influence things than Fallout 3 did.
On top of adding back in geckos, New Vegas has a whole new type of animal: mutated mountain rams called Big Horners.