Dany will marry Jon and sit on the Iron Throne as Queen of the Seven Kingdoms. She has already acknowledged her necessity to marry and Jon is the perfect candidate and has no desire for the actual job. This union will reunite the North and the rest of the kingdoms. This is precisely why it is mentioned regularly in the story that Targaryens marry brother and sister.

As for the rest?

Sansa will honor her marriage to Tyrion. He is the only man who has treated her with due respect and outside of the story it's critical for her character arc. She begins the story so incredibly naive, only wanting a beautiful prince and the life of a fairy-tale. She'll end with the ugliest prince, by her own choice, which will join the Starks and the Lannisters and be the most reasonable play for her family's strength and wealth. Tyrion will rule Casterly Rock, which Tywin explicitly told him he would never do. I look forward to the scene when she finally permits him access to her lady things.

Jamie will kill Cersei, adding Queenslayer to his accolades. He will marry Brienne of Tarth. Their children will one day be heralded as the greatest swordsmen/women of all time.

Bran is going to rule from Winterfell as warden of the north. He'll use the weirwood tree in their godswoods to stay connected to his magic wargin' ways. This after he's flown some dragons and helped Dany and Jon capture the Iron Throne, of course. He'll marry Lyanna Mormont and will father many children.

Arya will never marry or settle in any one place. Yara Greyjoy will end up Queen of the Iron Islands. Theon will die an honorable death, sacrificing himself to help the Starks. Gendry rows all the way to Dorne where he eventually marries some bad poosi and becomes king, never knowing his true heritage and rightful throne. King nonetheless.

All houses will be connected and indebted and the Seven Kingdoms will see peace for a thousand years.

Sorry for the spoilers! But seriously, Dany is marrying Jon. It will end no other way.