I usually don't mess with vampires in my games because as I read of them in the MM, they are, to me, one of those unnecessarily convoluted monsters that I don't feel like dealing with.
Specifically, what annoys me is level drain. Not that it happens, I am fine with it happening. What annoys me is the, in my opinion, vague assumption that any attack or "hit" from a vampire will consist of a bite, mixed in with other attacks.
In any and every other vampire lore, a bite is a specific and specially damaging attack. It historically isn't the first or most common move that a vampire makes in a combat.
In AD&D, it's my thought that a bite attack which results in the highly damaging effect of level drain (2 levels drained per incident OUCH!!!) should be one of those specialty attacks that the DM is intending before initiative is rolled. It should not be a given that a vampire is going to bite at every attack during melee.
When I read the Monster Manual and it says that a vampire causes 5 to 10 points of damage per "hit" (1d6+4), I am taking that as a blow from the hands/talons only.
This is how I plan to approach it in my games from here on out.