I always start with the Fierdsvain, simply because I love taking them over. My first city is usually Valonbray or Windholm, never Javiksholm. Valonbray is secure, with a considerable distance for enemies to cover, all the time under heavy fire. It's on a peninsula on a far side of the map surrounded by other fiefs to hand over to vassals. Windholm is not quite as defensible, but I love the idea of starting from a coastline and just watching as my Kingdom color slowly grows over the map. Windholm gets formidable quickly because I usually build a KotG order there, and they can hold a ladder like no tomorrow, with Silvermists or KotEG tearing up the enemy. Territory wise, Windholm is nice because you have castles surrounding it, easy to grab, and the villages sell a LOT of food, perfect for an army in full blown war mode.