You can't expect to survive the harsh wastelands surrounding New Vegas without the help of a few friends. Check out the dogs, robots, humans, super mutants, and ghouls that'll be helping you survive Fallout: New Vegas.
Not only do Fallout: New Vegas' companions keep you company, they deliver helpful perks to your character, just by staying by your side. Take Rex, or Cyber-Hound Mk. III, LEO Support Model, Serial Number B955883. Whenever this four-legged companion trots alongside you, unequipped chems, firearms, and ammunition will be highlighted for a short distance when you zoom the camera, no doubt because of his superior sense of smell.
Check out the PlayStation Blog Europe post by Bethesda senior community manager Matt Grandstaff for detailed bios on each of your Fallout: New Vegas companions, but be warned, there are spoilers over there.
Meet The Companions Of Fallout: New Vegas [PlayStation Blog Europe]