So there seems to be a growing theory that the White Walkers (The Others) are not necessarily the bad guys. i.e. They are only protecting themselves and expelling Man from their territory. One which was agreed upon thousands of years ago when the wall was built.
The theories keep using a quote from Martin relating to his thoughts the fantasy genres over use of the Dark Lord and evil minions concept
"Much as I admire Tolkien, and I do admire Tolkien — he’s been a huge influence on me, and his Lord of the Rings is the mountain that leans over every other fantasy written since and shaped all of modern fantasy — there are things about it, the whole concept of the Dark Lord, and good guys battling bad guys, Good versus Evil, while brilliantly handled in Tolkien, in the hands of many Tolkien successors, it has become kind of a cartoon. We don’t need any more Dark Lords, we don’t need any more, ‘Here are the good guys, they’re in white, there are the bad guys, they’re in black. And also, they’re really ugly, the bad guys. **George R. R. Martin, Assignment X Interview, 2011"
Appearance wise, in the TV shows the White Walkers are very corpse like and "evil" looking
In the books however, their descriptions are a little less clear. At some point they almost sound like Elvish looking creatures that a fair to look upon. Martin himself described them like this when giving guidance to comic book artists... "The Others are not dead. They are strange, beautiful… think, oh… the Sidhe made of ice, something like that… a different sort of life… inhuman, elegant, dangerous."
Their armor and even the way they walk with the above description sure makes them sound kind of like Elves in the Tolkien sense
"...He told me of the ice swords, and the reflective, camouflaging armor that picks up the images of the things around it like a clear, still pond..."
"...The Others go lightly on the snow and leave no prints to mark their passage. Their movements can be lighting quick.."
Much like the Tolkien Elves, the Children of the Forest and the Others have no place in man's world. But maybe instead of all sailing off into the West, they are coming to take back what is theirs.
This makes the whole distinction of good vs evil a bit more blurred
Also much like how Rhaeger or even Jamie was painted early on as being a clear cut bad guy simply because of the bias of the people you get their stories from, Old Nan's tales about the others could be colored with the same bias.
The TV show may have gone with a more obvious "bad guy" route though. They refer to the as the White Walkers instead of the Others and turn them into gaunt mostly armorless corpse like appearance to also convey more of the "bad guy" vibe
So basically one theory is The Starks are connected to the Night King, who married an other and brokered an uneasy piece allowing them to remain north of the wall and men to remain south. Over the years, this contract has been nullified as more and more men populate north of the wall, and now, with the rebirth of dragons, their is a new threat against them. So the time has come to clear house as their hands have been forced again. Jon Snow may be the one who can bring about peace again, not necessarily by good defeating evil, but by somehow establishing another middle ground type of peace, much like the Night's Watch commander who became the Night's King
Not sure how much of the last bit I buy, but I do think the others are not necessarily supposed to the absolute pure evil they are depicted as
