Pax East is in three weeks. The announcement of the 1080 Ti is rumored to be during that event. Wait till than to consider purchasing, as the GTX 1080 (non Ti) could possibly go down in price at that time.
Don't use the existing drivers for your new Pascal GPU. Simply download the latest drivers and let them install for your GTX 1080 (Ti). As far as brand, everyone has their favorites. I like the warranty and service of EVGA cards. I also like MSI cards and I'm considering trying my first Zotac card.
Addendum: I suggest that you list your full specs, including your power supply's manufacturer and model number. In addition it would be helpful to know the resolution you play and two or three games that you plan on...