Personally I choose Mr. House. While he is quite despotic and has little regard for individual human (although same could be said about any other faction) he is the only one with an actual longer term plan. Plus his ability to accurately predict eventual future events and lack of of petty feelings (no prejudices towards "races" that used to be humans, lack of interest in small time revenges, etc.) are also a bonus. Also he has already demonstrated that his plans tend to bear fruits (saving Vegas from nuclear holocaust, manipulating NCR into signing a treaty clearly beneficial to him). Maximum efficiency with as much as possible personal freedom is the best thing you can hope for when you live in a crapsack world. NCR under Kimball is in my opinion a shadow of what it used to be under Tandi presidency. Ironically the best thing it can hope for is loosing the whole Mojave campaign,as it would be the impulse to change it's decaying political body. Victory in Mojave would only win Kimball more support and promote individuals like Moore and Oliver. Caesars Legion is a bunch of murderous misogynistic Luddite slavers, best chance for future my ass. Bonus points for falling after its leaders (who unlike House isn't ageless) death. I tend to have mixed feelings towards wild card ending. On one hand it would be possible to Courier to create haven on earth with all his resources. On the other Courier is basically ax-crazy (judging from number of people he killed, whether those people deserved it is another thing), brain-damaged, half machine (hello Big MT and dr. Usanagi) half mutant (since most of perks are clearly mutations: Toughness (bulletproof skin isn't quite normal), Solar powered (healing factor PLUS superhuman strength while under the sun isn't either), not to mention rad child, atomic and the one that removes radiation over time) clad in power armor. He is basically good old Frank Horrigan MK. II, with a golden heart (if good karma) but still. Terrific enforcer, guy/gal you would call when you need a hole punched in some troublesome deathclaw, but I doubt he/she would make good faction leader.