I wouldn't get the 1080 yet. Wait for benchmarks. I'm sure it's a nice GPU, but you should take a look at the previous series.
The 980 wasn't a pretty great deal. It was only marginally better than the 970. The OC 970 models also were basically on par with the stock 1080. And an OC'ed 970 was actually around 330-350 dollar, while you would need 500 for a 980. So, for CB, the 970 was way better. For power? The 980ti arrived a year latter and stomped the 980. If the history repeats itself, the 1070 will be a better deal. So wait for the benchmarks to see if the 1080 really is a much better GPU or if it isn't.
I would count on a minor advantage. The 970 was a huge success, I believe Nvidia will prioritize the 1070 over the 1080 since it can be another sales driver. Just the enthuasiasts aren't that much into the 1070, but they probably aren't that much into the 1080 since these guys probably already have a 980ti or are waiting for the 1080ti.
The 980 didn't do so well because the 970 was INSANE. This generation the power of the 1070 and 1080 appear to be more in line with previous generations. An extra 2.5 Tera flops plus HB SLI should be worth paying the extra cash. Of course we'll have to wait for benchmarks to be sure but just going by what information we have it should be a good buy.