Most of us have at least a vague idea of how we think George R.R. Martin's A Song of Ice and Fire novels, and the Game of Thrones TV series, will end. But those expectations are shaped by the usual course of epic fantasy — and as Winter is Coming points out, Martin has maintained an ambivalent, arms-length relationship with that genre.
Spoilers ahead...
The ending most of us have in mind involves some permutation of people on dragons, taking out the White Walkers. Daenerys and Jon Snow are usually assumed to be two of those dragon-riders, and maybe they hook up in the end. But that's sort of a standard "heroic fantasy" ending, and this series has played with and rejected the standard elements of heroic fantasy all along, as the fansite Winter is Coming notes. The books' messy political storylines are at least as important as the huge heroic arcs of Jon Snow and Daenerys and the threat of the White Walkers.
Writes Rowan Kaiser:
In order to assume that the ending involves good triumphing over supernatural evil, characters and storylines that I like and consider critical have to be assumed to be less important than those of most important characters. This both goes against my preferences, and my understanding of the story being told. In my personal Game of Thrones, a fascinatingly flawed negotiated compromise serves as the climax, not a glorious dragon run.
I'm not sure how you negotiate with the White Walkers, but maybe there could be a negotiated compromise among the warring kingdoms that serves to keep the White Walkers at bay. In any case, Kaiser says that there are three possible endings for the series: one that embraces heroic fantasy, with a triumphant final battle, and one that subverts heroic fantasy, in which we see a great victory but realize that it was pyrrhic.
And then the third option is an ending that "rejects heroic fantasy, letting petty politics and Red Wedding-like events continue to dominate the story, leading to a deliberately unsatisfying ending." The real ending may be some combination of these three, depending on how much Martin wants to push the supernatural element versus the political/social element, says Kaiser. And of course, the TV show is looking more and more likely to have its own ending before the books have theirs. [Winter is Coming]