This site lists six mods that you can get from Fallout new Vegas Nexus.
There is a mod which fixes the constant lag, a UI improvement mod, a World brightener mod(I.e, less bleak, but still realistic), a mod which extends the gameplay beyond the ending(The creator is working on changing the faction territories to correspond to the endings), a centred PC mod, which gives you a much wider view of yourself in third-person.
There is also a fun little radio mod broadcasting different real life warnings and tips from the 50s about nuclear bombs and fallout.
