Well
I'd obviously choose New Vegas. Nice weather, not many super mutants. Fiends are alright. And there's NCR of course! If you ask me you'd have a better chance of survival in the Mojave Wasteland instead of the Capital Wasteland. You've got an avenue of CANNIBALS there! And crazy costume superheroes. Plus the irradiated water and mirelurks, more deathclaws, a ton of super mutants and centaurs, stations filled with ghouls, more radiation, and Enclave. That is the Capital Wasteland for Ya'.

Hmm, Hard one.
I'd probably go with Fallout 3. Once I step outside the vault, I'd probably try to head towards Megaton, to get some better equipment. Then I'd head out into the Capital Wasteland, where my fate awaits; become a Bounty Hunter, member of the BoS, or die terribly by Mutants.
You probably have a better chance of surviving in the mojave, But I'd probably be fine.
But I'm not going down without a fight.

That's a hard one. On one hand you would have to deal with constant heat in the Mojave. On the other hand there would be heat, cold and mild weather which means more to carry around with you. There are definitely more dangers in DC with the raiders, muties, irradiated water, and ghoul infested metros. In the Mojave it's more of a man vs. environment thing. I'm from the suburbs of Philadelphia and honestly I don't know if I could handle all that desert. I guess i'll go with DC. Mostly because I can't stand hot weather. And if this is post lone wanderer that we're talking about I could always go hang out in Vault 101 since they opened their door to the outside.

Mojave of course, more civilized, more water but humanity pretty well screwed, but something tells me that i will take a walk also in the d.c wasteland, the first thing i loved bout fallout 3 was the atmosphere the moody climates, with all those freaking eyebots with the enclave radio.. a really hard choice especially if you have play both of them so much time, nice post tough !

Tough, but I think D.C. I don't think I'd be able to handle the surrounding outside vegas or the cities. Think of the vast emptiness around Vegas. Big, sandy, dusty empty plains, that stuff scares me to no end so yeah i'd take the D.C. world of 3.

new vegas so i can make a army of death claws and cazadors and rule the wastes.

I'd say the Mojave Wasteland. There are less Super Mutants and the ones that are there are almost civil, and their bigger cousins, the Behemoths, aren't stalking the desert. The only danger I'd have to worry about is dehydration and a few poorly armed raider gangs. There is also some security by the NCR who are trying to create order in the wasteland so I'd feel a little safer walking the Mojave knowing they're around.

I think you would have to be crazy to choose to live in FO3 DC NV all the way! There isn't anything cooler than to be a gunslinger with the duster and desperado hat but instead of having six shooters, you would have energy weapons. You don't see this in any other video games

Eeh i love the DC. but I wouldnt mind drinking and have a chill time with some bit*hes! soo i think i would pick NV! hard choice really..

That's a toughy haha I really like fallout 3 because of going through ruined cities and seeing awesome fortress like the BOS location. But New Vegas seems so much safer in a way haha and a little more civilized .

I would stay in Jacobstown for friendly mutants, Novac for a nice home and a desert for some clean pickings( killing ants), or Goodsprings because its probably the only safest place in the Mojave.

New Vegas, all the way. Don't get me wrong, I know a lot of people love the really "apocalyptic" feel of Fallout 3, but I just love the Western atmosphere of FNV. It's a whole lot brighter, but its also something else. Its almost like the nuclear holocaust reset the Mojave back to it's wild western roots, where there's a lot of lawlessness and only a few men to dispense justice (or mayhem, depending on your playstyle) into the region. One things for sure though, that "Fallout" feel is in all the games, and that's the real reason I love it.

Do I have to be shot in the head first if I choose the Mojave? because I don't think I'd like that to be honest.

Other than that I'd pick the Mojave any day, DC is a chaotic warzone!