So, about the various Courts. My first inclination is to say "The different Courts/Houses are Different KINDS of vampires". I personally think it's cool when you have radically different power sets, and different expectations, depending on what Kind of vamp you're dealing with.
There are two different series I would personally look to for inspiration. Laural K Hamilton's Anita Blake series (I know, I know), and Jim Butcher's Dresden Files. Allow me to break them down for you.
Dresden Files
There are three kinds of vampire Courts shown. The Black Court is your undead, cross-hating, Bram Stoker's style vamp. Love their sorcery. The Red Court are actually bat-creatures, who wear a fleshy human shell, and have an addictive mind-altering saliva; sunlight kills them, and they can be killed like anything else, but tearing open their stomach paralyzes them as the blood they drink is lost. Finally there's the White Court, who are psychic vampires; they're the most human like (can walk in day, shield from typical detection). They drink life force, and they feed on it in different ways - lust, despair/anguish, or fear. They are very good at mental manipulation and playing with your memories/motivations/etc. To these, the opposite of their feeding is their weakness (true love to a lust vampire is like a brand; hope to despair, courage to fear, etc).
Anita Blake
You don't see a lot of different styles here; the primary here is the Lust-based vampire. But there are a few. There's a Warrior clan (who are to fighting what the incubi are to sex). There is a Nightmare - a manipulator of fear. There are also a breed of vampire that
rot; they dissolve, fall apart in a fight, etc. This actually makes them vulnerable to nothing but fire.
The thing that sets this series apart is the various powers vampires can have. Human Servants (an immortal human whose life force is tied to the vampire), Animals to Call (power over the lycanthrope of their animal type, as well as normal animals; one of the most powerful vamps in the world can control any type of lycanthrope), Drawing blood from afar (and other types of parlor tricks; another Most Powerful vampire could cause Earthquakes). Another of the Most Powerful could actually possess bodies, jumping from corpse to corpse.
I'm only vaguely familiar with WoD, so any similarity to the various clans are only coincidental:
- A clan of emotional/psychic vampires. You might have them all feed on one emotion, it be indvidually based, or there could be different types that are constantly seeking dominance over the others (or trade power every X century). They obviously will use powers of domination, those that do psychic damage, and daze. These guys could be serious terrors (literal Fear eaters) with fear keyword powers, or sick hedonists (Succubi/Incubi).
- Soul Eaters. Check out the Spirit Vampire in Open Grave, maybe reskin some Oni, as they have the Soul-Sucking motif down.
- Animal changers. Not just "I become a wolf", but think about the types of actual organisms in our world that suck blood. Misquitos. Flies. Leeches. Having a vampire rip its face off, underneath being a giant fly's face, while insectile wings sprout from its back? Or become a swarm of leeches? Totally freak your party out. Not to mention I think a praying-mantis style vamp would be cool.
- Something Exotic. The MM2 is going to have Pennangolin Vampirse in them.
A few other thoughts:
Each House could have its own inherent weaknesses/ways to kill them. See Open Grave for its mention of different vulnerabilities.
You could have a single House that is the black sheep of the lot. They're not "Good", but they are a hint more benign; either to their subjects, or they are just less ruthless and brutal to the others. They could even be a "Fail Safe": an exiled House (or a dirty secret) that, if the other Houses ever get wiped out, this House is to take up the kingdom's mantle, to prevent Whatever from awakening. Perhaps they are hyper-religious zealots, ascetics, or paranoid psychotics, hence hide themselves away. Their subjects simply "donate" small amounts of blood, keeping them fed while this House never splurges.
Other undead. Obviously, other undead are going to flock to this place, to either seek political power, or just take advantage of the situation. Intelligent undead are what interests me here. I'll pitch to you an idea:
[sblock=The Unkindness]In this land of blood drinkers, imagine how the Ghoul is seen. They are disgusting corpse eaters, or filthy creatures with no table manners.
The Ghouls could behave like bandits and barbarians - savage pacts at the edges of the kingdom that attack. They could be seen as servants; eaters of the vampire's scraps, guards beyond the Untouchable, etc. Or, they could be a Counter-Culture; a guerrila force, hiding in the shadows, acting like vampires (imagine a dinner party of ghouls, all dressed in fine clothing and powdered wigs, and serving a fresh corpse on fine china), or acting like anarchist revolutionaries, because they are jealous of the vampires.
I chose the name "The Unkindness"; ghouls make me think of ravens, which are smart carrion eaters. A gathering of ravens is known as an Unkindness.[/sblock]
Another possible resource is Ravenloft. It has different vampires based on Race. There's also a PDF or two I have on my machine that I could send you.
The video game Legacy of Kain I and II dealt with different types of vamps, so you might look into that as inspiration too.
