the 3770K will be no practical difference with a 3570K in gaming.
you can probably get away with the AS Rock Extreme 4 instead of the Extreme 9
the 670 is fine foir single screen gaming. for three screen gaming, you want two 670s.
I;ll suggest a 1TB HDD to act as a storage drive
the 800W PSU is overkill for a single 670, where a single 550-600W PSU will do. for SLI, 700-750W is preferred. Go with a top-class brand (Seasonic, Corsair, Antec, XFX, PC Power & Cooling) at around 750W and you'll be good for two 670s in the future