Well, first off the NCR is not the best choice for the Wasteland. Some may disagree, but they just aren't organized enough to do so. They take over settlements however they can (Bittersprings), make enemies when they do so, and then fail to enforce their newly acquired land. The NCR's troops are spread too thin for an effective control of the Wasteland and they will eventually crumble.
However, I also think that CL is not good for the Wasteland. Josh has brought up some good points, but CL is not going to take hold of the Wasteland in a good way. The idea of slavery and sixism is cemented into the CL and even if they manage to take over the entire Wasteland for years this standard will still be in effect. Caesar is the main force behind them, and if he were to die CL will have monumental troubles to overcome. When they manage to take over a place (Arizona) they are good at suppressing violence, but they do so out of fear. The entire Wasteland would be ruled under fear and if you aren't born into the Legion, I can't imagine that being the environment you would like to live in.
As for House, I like his long term goals of New Vegas. Though they may only apply to New Vegas in the beginning, it is not unreasonable to believe that couldn't extend further throughout the years. Money is needed to rebuild, and New Vegas generates that money. With enough money anything can be done, and unlike NCR or CL who have very little, Mr. House could use that money to commission all sorts of projects benefiting mankind. New Vegas could expand and become a safe haven for members of all classes; Freeside could be improved, Westside could be improved, the list goes on. Imagine the whole map in New Vegas being a part of the Strip, rich with new casinos, shops, hotels, and restaurants.
Personally, I go with the Enclave though. Many disagree and I have advocated this point in nearly all my posts regarding the Enclave. President Eden's FEV virus (Richardson's was different) would kill basically everything infected with radiation poisoning, even of the most basic degree. Granted, all people in the Wasteland would die, but so would all the hideous monstrosities killing those people. Enclave would be able to expand with a new human race unaffected by radiation birth defects and the patriotism of America. After 100 years it is not unreasonable to assume a good part of the Wasteland would be populated by towns and citizens of a new government that is capable of enforcing its position.
These are...pros to you? :cryvaultboy:
Haha, worrying indeed. :unsure: