Maybe like you, I'm tired of both subtypes of the undead. Still, I am unable to resist a zombie movie. I was thinking about this phenomenon after having seen Zombieland twice in two days. In both cases, we're not really sure what these creatures are about. There are two strands of zombies: those who are crazed cannibal creatures, who might as well be dead; and those who are (un-)dead but still ravenous. With vampires, there are the ur-vampires and there are the made bloodsuckers.
We accept without much comment that these creatures naturally won't feed on each other and would rather starve for humans than turn on each other. The more logical notion would be that their populations would quickly implode through internecine conflict. There is also the ambiguity in most representations of when a victim is killed outright and when said victim is turned. Sometimes there is a logic to the procedures, sometimes not.
We put up with a lot of non-sense.
Why do we like zombies so much? I am afraid that it is the guilt we feel in "us and them" thinking. There is no hesitation in creating an "us and them" out of zombies, no moral or ethical ambiguity, what fun. And still we get to off humans. Grim.
What's the attraction of vampires? The empty husk and the need to fill it with something from us. We may see it in euro-trash or homegrown charmers. We want the rush of knowing that our life energy has undeniable attraction to some other creature, even if only for consumption. We may find it scintillating or titillating to imagine the kind of creature that lives off life energy, but in the end we are looking in a mirror and seeing only ourselves. And the blood we would let drain for a sense of our importance.