Spoiler free's the way to be!
Harry will return, briefly, to the Dursley's accompanied by Ron and Hermione. They will proceed to the Burrow for Bill and Fleur's wedding before visiting Godric's Hollow, where they will discover an important detail about the night Harry's parents were murdered. They will find the locket Horcrux RAB retrieved, as it was at Grimmauld place. It was either sold by Mudungus or taken by Kreacher (probably the latter). The three of them will proceed to search for the other Horcruxes, riding on the back of a dragon sometime along the way. They will also discover important information about Dumbledore's past and perhaps talk to his brother Aberforth (who is likely the bartender at the Hog's Head). Once all of the Horcruxes have been found and destroyed, Harry will go to face Voldemort. He will sacrifice himself, by choice (emphasizing the series anti-fatalist themes) in order to give Voldemort a fate worse than death. Harry will go beyond the veil and be reunited with his parents, Sirius, Dumbledore, and the other characters who die in book seven. On that note, Hagrid, Snape (who is cruel but loyal to the Order, none the less), and the Weasley twins will die. I would also wager that Pettigrew and Lupin will die as well, as all four marauders dying seems fitting somehow. Harry will discover at some point along the way that Dumbledore planned his death in order to protect Draco from Voldemort. Draco will redeem himself. Snape will sacrifice himself to save either Draco or Harry. Percy Weasley will not redeem himself and may end up betraying his family to the Death Eaters (which could lead to the twins getting murdered or some such). Draco's redemption will emphasize that not everyone from a bad family goes evil while Percy's lack of a redemption will emphasize that not everyone from a good family is brave. While Draco is by no means an upstanding individual, his redemption will reinforce the difference between being mean and being evil (something that will be shown as well in Snape's story). Pettigrew will repay his lifedebt at some point. Neville will go on to be the Herbology teacher at Hogwarts (which will indeed reopen). Ron and Hermione will end up together, unless J.K. Rowling has decided to be cruel and kill one of them. In which case, Ron will die and Hermione will take up with Ginny and the two will live happily ever after, the end.