Hiring: potential vs. experience

How often have you been faced with the dilemma of being unsure of whether to hire an applicant for a position in your organization? Their resume and past experiences suggest that they should be able to do the job, yet something intangible just doesn't feel right. Or perhaps in anticipation of changes in your industry and business you have decided to create a new role, but are unclear as to exactly what you are looking for in the right candidate?