I'm in Los Angeles, one of the markets (along with Dallas and probably New York City) that would most affected by a potential TWC/Charter (or Cox or Comcast) merger. The current neighborhood where I live is a TWC territory that was once part of Comcast (and before that AT&T Broadband, MediaOne, Continental Cablevision, and American Cable Systems) just prior to the Comcast and TWC acquistion of Adelphia Cable back in '05-06. Time Warner had already been in the market since the late 90s/early 2000s, back when they acquired the old Paragon and United Artists Cable systems; now by the virture of the Adelphia acquistion, TWC controls almost the entire city of Los Angeles (except San Pedro, which is Cox territory), most of western and central Los Angeles County, and the northern half of Orange County. Charter covers Long Beach, Lakewood, the eastern San Fernando Valley (Burbank and Glendale), and good chunk of the San Gabriel Valley, and most of the Inland Empire.
Charter would probably benefit the most buying TWC, as they would cover every cabled home in greater Los Angeles not serviced by Cox (and not counting U-verse, Fios, or the DBS'). The same thing in the Dallas-Fort Worth Metroplex...TWC serves the Dallas side of the market, while Charter serves Fort Worth and the western suburbs. New York City would interesting, where I could see Comcast or Cablevision acquiring the TWC systems there, where geographically it makes the most sense.