This is a living document to run up through Season 4. Wikias have way too much information and can spoil things and I wanted to reference (as I watch) a concise form and came up with this. There is lots of stuff missing (characters and places.) Please let me know of any corrections or additions and I will update this information. From here forward, I will save a version of this after each episode. Unfortunately I don't have time to go backwards and do this for every episode prior.
War of Five Kings
Territory House King Status
#1. King of The North: Robb Stark; Killed
#2. King of the Iron Throne: Baratheon of King's Landing (Lannister); Joffrey Baratheon; Alive
(Territories now include The North and The Riverlands and soon to include The Reach.)
#3. King in the Narrow Sea: Baratheon of Dragonstone; Stannis Baratheon; Alive
(Territories now include Stormlands.)
#4. King in High Garden: Baratheon of Storm's End; Renly Baratheon; Killed
#5. King of the Iron Islands: Greyjoy; Balon Greyjoy; Alive
* Stannis was in charge of a Navy that defeated the Greayjoy Fleet a number of years before the War of the Five Kings so there has been bad blood between the Greyjoys and Stannis in the past. (S1E7.)
* Battle of the Blackwater: Lannisters held back the Baratheons and Tyrion has the scars to prove it.
* Stannis killed Renly using dark magic: Most of his followers at Storm's End sided with Stannis.
* House Tyrell is brokering for peace with a betrothal of Margaery to Joffrey Baratheon. That will firmly
put 'The Reach Kingdom' in the hands of Baratheon of King's Landing (Lannisters.)
* Red Wedding: Lannisters used the Freys and Boltons to kill Robb Stark.
Game of Thrones: Threads at the TV Critic