Agamon
Adventurer
But if you're doing an entire "Buffy" campaign where every other week the PCs are going to be fighting vampires, you really don't want to give the group a near-trivial way to take out those creatures.
If I'm doing a Buffy-style game, I probably do want a way for the PCs to take out vampires trivially, just the Buffy and the Scooby gang did. You just don't want the Big Bad to be taken out like that.
Conversely, if I'm doing a rare vampire encounter in a regular D&D game, it puts a damper on the encounter if it's taken out quickly. Than again, I like when players come up with cool ideas to overcome challenges, so I wouldn't have a real problem with it.