Which skin texture mod do you like the most for Fallout NV?

By skin texture I assume you mean race. I would argue that the top shelf mod would be Fallout Character Overhaul. It adds a ton of custom races for many story characters such as Ceasar, Boone, Lanius etc. It also adds a lot of great hair textures, facial hair textures and ghoul textures. It also has stuff like animated sweat, feral ghoul glowing and of a lot of addons for other mods, like BBD, Someguy series, and Willow. Overall great mod. I would suggest it.

FCO by far is the best "next gen" skin mod for New Vegas. It adds in brand new races that are reimagined versions of the vanilla races and then some. It adds in new ghoul races which I think are far superior to the vanilla ghoul races and adds in races for specific characters like Boone, Caesar, and Cook-Cook. Right out the box, it is probably the best RACE mod for New Vegas.

Another great one is NVR3. It not only adds in new races but it also redesigns certain character faces to match their voice better. Like for instance, Lieutenant Romanowski. Listening to this guy while looking at his face is fucking glaring. He looks like someone that lives in Gilroy, California but sounds like he's from Compton.

Example: http://fallout.wikia.com/wiki/Romanowski

NVR3 redesigns his face so that he looks more suited for his voice(A.K.A make him a black guy since the character is voiced by a black guy). NVR3 also goes out of its way to redesign some of the more gruesome scenes in the game. Like for example, the inside of Nipton Town Hall looks trashed, but its dead victims look alright for being dead. NVR3 changes that by making the dead residents look like slaughtered meat. It is actually really gruesome, but it is supposed to convey the original message of what happened to Nipton.

I use Type 3/6m Skin Texture and Robert's. Breeze has some appeal, but ultimately, I just prefer Robert's.

And I know there's Type 3m and a few others, but Type 3 really seems like the best in my personal opinion. Type 6m, also used Type 3 textures.