@danklamp: crippling hunger of living tissue or fluids, weakness to light that can range to incomvenience to mortal danger, excessive sensibility, deadly allergy to some fruits/vegetables, incapability of healing without external help/sustenance, exotic requierements in accomodations, underlying madness, mortal weakness to representations of divine power/divine power itself, inability to choose on crossroads, inability to enter buildings without the owner's explicit permission, obsessive compulsion of counting spilled grain of a defined type...
And that's just vampires! It depends of region and folklore, though.