There are four basic combinations that you can pick for graphical options in Fallout New Vegas. HDR probably looks the best out of the options, even without AA.

None with Zero Anti-aliasing


None with 2x Anti-aliasing


Bloom (no AA)


HDR (no AA)


Note that in general, you can't use Bloom/HDR in combination with AA reliably. Which is an annoying restriction that will hopefully be fixed in a patch.