First ending I did was the Legion, and I still want to play the Legion role again. xD
Theres a quest for Forlorn Hope that if you take out their pratically leaders, as well as their doctor, which I'm sure you've done, you get a machete named Liberator or something like that. I found that one a fun one, simply because its you vs. an entire encampment of NCR, when I did it on the side of NCR, I'll admit, it was to easy to kill the Legion with their machete's and my Oh, Baby!
As well as, in the NCR side, you gotta go against the Heavy Armored troopers.
If you like I have done the other endings.. be suspectant to have to kill a lot of people seeing how 70% of the entire map it pretty much NCR.
Thank-fully, if you do go with the Legion, you get a lot more places you can raid. EX; Camp Gulf, Camp Forlorn Hope (Respawns) Ranger Station Echo, and Foxtrot.
Reason why I probably went to the Legion is because they was probably the most challenge.
Wish Betha didn't cut them as much as they had, I'm not sure if they think it would be the least active (understandable) or just shocked it was at all active. You'd think that maybe women players wouldn't go for 'em like they had, but I'm pretty sure some women like being treated like jack and others liked the challenge, and maybe even just because they like men in skirts.