Sabat vs Camarrilla
The biggest question you need to answer is Sabat or Camarilla but to do that you probably need a little more information. The flavors of each group will be very different as will the styles of the two story tellers. Most base clans are available to either side, as are the independent clans. However each side has two unique clans only available to them.
Base Clans: Both the Sabat and the Camarilla have members of all of the base clans. In the case of the Sabat they are refered to as Antitribu.(EX. Ventrue Antitribu) Each clan covers a broad range of vampiric archetypes:
Gangrel : The Gangrel embody the idea of vampires as predatory feral demons. An upper level in the feeding chain with little or no interest in humans as anything other than food, they represent vampirism as crude predation and evoke ideas of basic instinct, untamed ferocity and freedom that are commonly associated with predators.
Venture : Ventrue are regal vampires who value power and dominion to the point of obsession, self-styled “lords of the night” they represent vampirism as a metaphor for maddening power, like Bram Stoker’s Dracula.
Daeva : The Daeva evoke the image of vampires as seductive, decadent, sexually transgressive predators who blur lust and hunger together, equating the act of feeding with sensual pleasure.
Mehket : The Mekhet are mysterious conspiratorial occultists, obsessed with knowledge and information, who hide in the shadows and manipulate others from afar.
Nosferatu : Nosferatu vampires are the repulsive, yet fascinating, alien and hideous monsters of legend (such as Count Orlok of their movie namesake).
Independent Clans: their are several independent clans but for this game their are really only two important ones, The Sangiovani who are a Italian clan of Vampire Necromancers, and the Assamites who are a clan of skilled assassins who take contracts to kill other vampires.