i want to get the 1080

[Rockets13]

how long after the 27th will the 1080 be sold for $600. also would an i5 6500 bottleneck?

 

[Gam3r01]

We cant answer that, nobody can. It will be quite a while most likely.
The i5 wont be a bottleneck.

 

[Chugalug_]

The i5 will not be a bottleneck for the GTX 1080.
I highly doubt that any models will be sold at the $600 mark, as most AIB partners have to make a profit off selling the card.
It is speculated that these cards will be showcased at computex and sold in June.
This is further supported by Gigabyte's facebook post teasing their Xtreme Edition GTX 1080 'Coming June 2016'.

If anything, the Galax card will be the cheapest, as it has a budget oriented design, although it looks like a garbage reference card!
Given that you're getting a 1080, i'd go with a cooler from EVGA, MSI or Gigabyte with a light overclock and cough up the extra 20 or 30 bucks.
Just giving my 2 cents, but whatever choice you make is up to you!