So what storylines from the books are now pretty much over?
The Stannis march (if it follows the TV show) seems like a huge waste of time considering that Sansa and Brienne are nowhere near Winterfel at the end of the last book. Also, I don't believe Stannis killed off his wife and daughter yet, so I am not really sure why so much time was dedicated to Stannis in both the TV show and the book.
Eventually the Reek/Sansa storyline will have to mesh up to something similar in the book, so I think Reek and Sansa will head south to find Littlefinger and let him know that Stannis' army has been defeated. Is there another army that Littlefinger could use to re-take winterfell?
With that said, I'm not convinced Stannis is dead. The only major death (if I am remembering correctly) that we didn't see directly either in the book or the TV show was the Hound. In the book there were plenty of other hints that "confirmed" it, but not so much for Stannis.
I don't believe John Snow is dead for a few reasons. The first, he is too integral to the plot. Second, they made an emphasis to show his blood in the final scene. Combine that with Melisandre's ability to do blood magic and I think she saves him. I think the only person he will take revenge on is Alliser Thorne and he will forgive Oli. I suppose it is possible that he then calls on the wildlings and they are used to re-take Winterfell, but I am not sure what their motivation would be.
Just some musings.