A ghoul, or a normal human, who you can Ghoulify.
This seems to add alot of credit to the, "Scared of Radiation" theory.
http://images1.wikia.nocookie.net/__cb20101016215155/fallout/images/thumb/8/85/Mr_house_human.jpg/140px-Mr_house_human.jpg
http://images2.wikia.nocookie.net/__cb20101016215223/fallout/images/thumb/4/4a/Mr_house_Coffin.jpg/140px-Mr_house_Coffin.jpg
http://images4.wikia.nocookie.net/__cb20101017095406/fallout/images/thumb/d/d9/Mr_House_Dead.jpg/140px-Mr_House_Dead.jpg

he is not a ghoul he a rotting corpse

Hes not a rotting corpse, hes a human being whose cryogenic chamber sorta-kinda failed to fully work so his mind is still fully functional his body just looks like its been zombie-fied!
Get back, ya zombies! back! (but we just wanted to trade some stimpacks....) BLAM BLAM BLAM i said get BACK YOU ZOMBIES!

He's a cryogenically frozen human trying to survive for 200 years... this is NOT a spoiler in any way.

As long as hes not a computer, I am bored of that now.

He is the Carrion Lord of New Vegas, for whom a thousand gambling chips are sacrified every day, so that he may never truly die.

The Black Trucks of the Vegas PD go forth each day, seeking gifted gamblers to sacrifice to fuel his life essence.

Although once a living man, his shattered body can no longer support life, and his will is only kept intact by the vast riches won each day in his casinos.

For in the Mojave Desert of the Far Future, the House always wins.