You could combine the two like SUSAN PETREY's short story collection
Gifts of Blood -her race of vampires are called the Varkela, peace-loving healers who exchange medical care for small amounts of blood called the blood-price. Set on the wild steppes of Tsarist Russia, the healers work amongst the diverse groups of people inhabiting the land, the Cossacks, the Turks and the Tartars.
Tragically the author died accidentally mixing sleeping pills with alcohol but the race is very real seeming and 'touchable' - they make mistakes and have stupid bad habits. Great stories.
Crosses are also solar symbols, and some authors throw in the idea that Crosses are psychosimatic.
In legend, garlic is a symbol of life, but you could throw in the fact that garlic is a natural antibiotic.
I guess the things I like best about the traditional fantasy/horror archetypes is when they have a somewhat believable explanation. When I am in the Dresden books and demons are 'facts' having Thomas tied to one that makes him a type of vampire, is believable and after that it is the characterization not the vampire shtick that makes him interesting.
Any character who does things without a believable motive just because they are 'born that way' - doesn't fly for me, unless you are trying to create a race of beings to be straw bad guys for the main characters to mow down (ie Zombie movies, orcs from LoTR...etc)
I liked some of the explanations from
Those Who Hunt the Night when it comes to vampires - that vampires have an incredibly persuasive psychic perception domination ability that allows them to seem to move faster, and change form, and be unbelievably beautiful, but only when the vampire is well fed - like an illusion version of the reds in Dresden.
Some ideas I'm waiting for someone to develop with vampires:
1. vampire hunters who infect themselves with Argyria which causes silver to collect in the hair follicles and turn the skin blue or grey -would also make them dangerous to bite if the silver allergy was in play. -
http://www.rotten.com/library/medicine/quackery/argyria/While Argyria has no real side effects aside from a slight itching, the condition is irreversible since silver becomes trapped in the deepest layers of skin
2. Vampire Saliva is found to have medical properties... -
http://www.physorg.com/news170661506.html -
"The component of the saliva of this tick... could be the cure for cancer," she told AFP. She said she stumbled on the properties of the protein, called Factor X active, while testing the anti-coagulant properties of the tick's saliva -- the way it stops blood thickening and clotting so the tick can keep gorging itself on its host.
The protein shares some characteristics with a common anti-coagulant called TFPI (Tissue Factor Pathway Inhibitor), specifically a Kunitz-type inhibitor which also has been shown to interfere with cell growth. A theory that the protein might have an effect on cancerous cells led to laboratory tests on cell cultures -- which exceeded all expectations.
As far as Shamen are concerned - I don't know why no one (as far as I have seen) makes them as real as Butcher or Rowling can make wizards. Why can't they be ER doctors, veterinarians or paramedics?
I don't mind if you postulate a spiritual world but make everything have certain sets of rules. In Tim Powers,
On Stranger Tides magic always had a smell that accompanied it and magic battles had a mage forcing a perception onto someone else mind - something that if the attacked person had a concussion and was disoriented, made it virtually impossible for that person to be attacked because they couldn't hold the image in their mind.
Things like that can make or break a story for the reader, as long as the characters are 3 dimensional.