I Hired a Zombie: The True Cost of a Bad Hire
mashable.com
mashable.com
While I agree that it's important to make sure you hire good employees, "because I can" is not a good reason to make the hiring process as painful and drawn out as possible.
IMHO, the "cost" of a bad hire is some multiple of their salary-- more like 200K-1M. Even worse if you add-up lost customers.