Let's break it down into these questions:
1. What is your favorite faction in New Vegas?
2. Which one would you like to control Vegas?
3. Which one would you like to control Mojave?
4. Which one would you like to control entire Core Region and Arizona?
5. Which one do you think has the best key-ring parties?
6. Feel free to explain in detail as to why you believe that [faction] is best suited for the job.
Have fun discussing and turning this into another Legion VS NCR discussion. -_-'
Note: I added House and Yes Man because if I didn't people would just start complaining about it so now they're up there and ain't going away.
7. Hmm, what faction from FO1, FO2 or Van Buren would you like to have been included in New Vegas that wasn't?