Legion of course, I don't wanna help any small timers, and none of the other major factions has ideals that I agree with.
Sure my life would be harsh, with constant training and skirmishes.
But at least I do something to help the greater good.
Even if I just manage to take down 3 NCtRoopers I'd still have helped Legion.

Either the NCR or Lyons Brotherhood, I agree with both of their ideals and I think they can do a lot of good for their respective communities.

NCR 1st Recon.

NCR, as long as I could go back to their own land and live a (relatively) easy life.

Hell just the NCR anyway

The Enclave>Easten BoS>Western BoS>The Kings>Boombers>Everything Else>NCR

First off I said the Legion not Eddie. I hate that man, and the Legion would be so much better off with his death.

My love for The Legion comes from unification. Out of all the faction presented thus far in the Fallout universe only one has any chance of uniting everyone together under one banner. Only one faction has any hope of expanding from ocean to ocean, and that is The Legion.

Yes there is a lot wrong with them, and they are a brutal bunch. However the wasteland needs that. It needs cleaning, and not the Enclave kinda cleaning, but the cleaning of eradicating the over abundance of drugs. With time, and necessity The Legion will change. Right now The Legion are what they need to be.

On the Followers front I love there dedication. I like the fact they work outside the major factions. Helping everyone, and not getting tied up into the politics that are surrounding them. They do what they feel is right no matter what those around them may say.

I'd actually have to disagree that the Legion has the best chance of uniting the former territories of the United States. They've got a highly unstable power structure. I foresee succession of power to be a very big problem for them in the future.

Lyons Brotherhood, I get power armor, energy weapons and the sastisfaction that I'm doing something that matters, not just hording tech. But if push comes to shove I'd join the western Brotherhood, become a high ranking member and hope to change things for the better, like another user said.

A joint operation between BOS and NCR.

There would be a minor period of... confusion. However everyone is to afraid of Lanius to rebel to much. Even if canon says Eddie, and Lanius both die the Frumintarii would get things back in order rather quick, and I can see Vulpes Inculta rising to the top real quick.

Vulpes Inculta has the mind to mold The Legion into something beautiful, and horrific.

Lanius no matter what lies Eddie tries to spread has the heart, and belief in the cause to do the same.

I think I would join the Mormons.