I put Vampires more in line with the World of Darkness style. There are different kinds, all require human blood to survive. The first Vampire was Cain, a vampire may create another only by an act of will and a ceremonial(or at least special) bite. As generations go on, they become weaker but more resistant to the sun. 4th Generation down to 1st are very harmed by sunlight, etc.
They are not repelled by Garlic, or maybe they are as much as humans are (which could be substantially). Holy Water has no value against them as such, only deeply held faith may work there. So, Holy Water isn't what works, it's the person's belief that Holy Water will work. This works for many things, so a devout Capitalist may turn vampires with his faith that his money will save him.
Also, some Vampires can raise the undead. Weak undead are easily put back down, and cannot cross running water. Strong undead (just below the level of the Lich) can cross small bodies of running water, but nothing as substantial, as, say, the Rhine or the Mississippi. The Undead cannot survive over Seas or Oceans.