Man this thread moved fast since yesterday. I want to reply to a few things.
Firstly, the issue of NV being a "giant DLC". Let's face it; it basically is. There's some new engine features here and there, but New Vegas is mostly just an alternative to FO3. It's what FO3 could have been from the start. FO3 is the less intelligent, slightly illiterate, duller little sister to New Vegas. NV uses the same textures/artwork for the most part, but there's lots of new content too. Combat is the same, questing is the same, the wasteland is the same drab brown expanse of dust and dirt. 90% of New Vegas could have easily been implemented as a FO3 DLC; there's even some suspicion that they took some scripts from community mods and used it for some of their "new" features.
But hold up a second, because I'm glad they didn't do that. If you didn't put money down on FO3 yet, I would wholeheartedly recommend buying New Vegas instead and just forgetting FO3 even exists. Even if it re-uses all that stuff, it uses it in a good way. Obsidian paid careful attention to every detail. Sure it's still as crashy and buggy as FO3, but that's Bethesda's fault, and they're already churning out patches for it.
The new creatures are well textured and animated; in this way, they do stick out from the old Bethesda models, which I've always thought were arse-ugly. NPCs, however, actually sound like individuals this time around. It's hard to tell exactly how many voiceactors they used, but I haven't experienced "clone-syndrome" yet, besides them not having tweaked or expanded on Bethesda's ridiculously limited facial customization limits. I guess everyone's just a cousin of everyone else this time, rather than a straight up clone...
Anyway. TL:DR; Yeah, New Vegas could have been created in the GECK for the most part, but that doesn't make it a bad game.
Now, someone asked about the combat? Yeah, it's kind of shooter-y in that department. Third and First person views in or out of combat. The VATS system lets you target specific body areas, to cripple limbs or focus on weakspots. You can go unarmed or with melee weapons if guns aren't your thing, and there's an assortment of explosives, grenades and mines you can use too.
Btw, I know a couple of people downloaded the ammo loot mod I posted, I'd love to hear about your experiences with this. I'm hoping it's subtle, but not too subtle that you never find anything. Personally I spent about half an hour last night rooting around in bins and boxes and didn't find anything. I may have to tweak the numbers a bit.