NZ $1600 Gamer Build

Hello all, first post on here after looking for 2 years.

So here goes

APPROXIMATE PURCHASE DATE: the closer the better
BUDGET RANGE: Approx $1600NZD
SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: gaming, surfing the internet, watching movies
PARTS NOT REQUIRED: keyboard, mouse, monitor, speakers, hdd's
PREFERRED WEBSITE FOR PARTS: Pricespy
COUNTRY OF ORIGIN: New Zealand
PARTS PREFERENCES: AMD AM3 & ATI 5000 series
links for 3 builds on Pricespy that I am looking at
2x 5770 X3 890GX
5770 X4 790FX
5850 X4 785G
OVERCLOCKING: Maybe (if I will then standard voltages only for CPU & GPU/s with appropriate cooling)
CROSSFIRE: Yes / Maybe
MONITOR RESOLUTION: 1680x1050 currently then 1920x1200 once I can afford one

Which build is the best bang for buck for gaming and has the best upgradeability for the future

Thanks for the help