Any one besides a founders edition or blower style that isn't >$100 over msrp.... but steer clear of the bigass zotac one. that one is bad from what i hear.
Watch prices right now they are 400 over the normal price on amazon and eBay and Newegg. Unless sold by Newegg or amazon actually and not a third party
EVGA 1080 TI KINGPIN or GALAX GTX 1080 TI HOF
Those are binned cards with HOF slightly outperforming on average thanks to the ridiculous over-engineering on the power delivery