I had another idea but I don't know of its quality.
We all know White Court vampires feed off of emotions like terror and sex. I want another court, let's say Purple Court, that feeds off of feelings of faith and loyalty. They would be a much less organized court, maybe not even really knowing of the existence of others. They would be the most human-like of all the courts, except for their two big traits
1) They have no innate strength or knowledge, but they are basically very fast learners.. They improve faster than humans, so for instance, any given Purple Court vampire who does not work out may not be stronger than any given human who also does not work out, when they do, they improve very fast; thus a vampire who does work out a lot would be very strong. Same goes for things like practicing firearms, studying a subject, etc.
2) They feed off of the faith and loyalty of humans. They are almost always in the positions of religious and military leaders. While they passively feed off of the feelings of those they inspire, they can also take those feelings and magnify them in humans, doing this like whipping them up into a rage, or religious fanaticism (not in a negative way, just a YES, GOD IS SO AWESOME WOO kind of way)
My character would be a military-type leader with a cadre of 3 or 4 humans who are utterly devoted to him. They are ex-Special Forces-type characters who are each proficient in firearms and melee combat themselves, but the real power is that the vampire can use his only power to turn them into raging, frothing warriors who gain strength and agility and ignore pain in order to protect the vampire. At the same time, he inspires loyalty by fighting right alongside them and protecting them as he can.
/edit: To drag in as comparison another huge geekery of mine, think of the not-murdering-asshat Commissars in Warhammer 40k; part of their job is to inspire the troops to great heights of bravery and inspire righteous rage in the troops. My guy would be very much like that, but also with a slight psychic component.