This whole debate comes down to peoples definitions of what a Vampire is. Some say Physic Vampires are only spirits and some say any physical person one who can drain someones energy is a Physic Vampire. Of course anyone who does energy work can in theory drain someones energy so that makes all of us potential Physic Vampires.
Personally I believe that there are spirits who are very close to our idea of a vampire. I believe they are the true Physic Vampires and just because you can drain energy it does not make you a "vampire" it makes you a person who knows how to work with energy. Also Incubus and Succubus I believe fall are different than Physic Vampires and are a completely different type of spirit.
while the dracula archetype is not real [despite claims of those who drink blood and say they are] there are physical beings called psi vampires [or psychic vampires] who tap into a persons aura [i believe] to drain their energy.
the dracula vampires are found in the astral, not the physical, though why people keep insisting on becoming a vampire is mind boggling to me.
Vampires may or may not exsist however vampires are not spirits they are classified as a mear "creature" and I do not belive you can transform into s vampire because transformation spells are not real.
@ Jay incubus and succubus are sexual demons, mostly from the bible if memory serves. succubus is male and incubus female. they tend to mate with humans because... we're apparently the hottest things around [can't remember] you can call upon one very easily [too easily as with anything imo] but like everything summoned, they are far harder to get rid of. they are not vampires. http://en.wikipedia.org/wiki/Incubus should explain it.
Personally, i believe in vampires and i think they are starting to develop in our society. I don't mean blood-thristy vampires with claws but people who are starting to develop their abilities. Those are people with large canines and, in my opinion, rich in keratine, the protein which is present in the hair and nails of mammals.
These abilities may develop during the following decades and, i don't mean that they can be used to cure diseases, but to make a difference between people around the world if these abilities are traced.