IMHO, for 1080p alone, either is overkill.
Still, i'd decide based on their price difference, if it's slim, get the 1080, otherwise the 1070Ti.
Since you won't upgrade in the near future, it will probably take longer than 3 - 4 until the 1080 is outdated for 1080p(While running everygame on Ultra, that is) alone so you'll probably be satisfied with it even beyond that time limit.
So, basically, you'll have a beast of card being hold back now by your monitor res but as time passes the leashes will loosen