Go with the 1070. In addition to the extra 2GB VRAM, it's slightly faster by default and will itself have some degree of overclocking headroom. A core overclock resulting in a 1470MHz boost clock on the 980 Ti represents an increase of 10% and I'd be surprised -- nay, shocked -- if you couldn't hit that (+10%; 1851MHz boost) on the Gainward. Even some FEs can sustain ~2GHz.
There's no need for a UPS unless your PC absolutely needs to be on 24/7, but a surge-protected power board isn't a bad idea. Many come with a warranty that covers damaged devices up to $x, but as you might expect there's a lot of fine print there. (I don't have any recommendations myself, but someone here might.)
Okay, thanks. I'll just go for the surge protector.Surge protector sure, but I wouldn't necessarily recommend a battery back up unless you really needed one.