Looking to upgrade from my 460 SLI setup with an eventual goal of running a tri-monitor setup within the next couple months. The 460's have served me well and still hold their own against modern games at 1080p, but I don't think they'd hold up in a 2D multi-monitor environment. I also want a bit more longevity, so that's why I'm looking at either the 680 or 7970. Here's my current setup:
MB: AMD Crosshair V Formula
CPU: AMD FX 8350 @ 4.2GHz
GPU: 2x PNY 1GB GTX 460 @ 800MHz
RAM: 2x 4GB Patriot Viper Xtreme DDR3 1600
PSU: Corsair GS700W
The 7970 is faster and cheaper, and Eyefinity is better than Surround. Go with the 7970.
As to the eyefinity setup, I've read that the AMD cards are very particular as to what output you use. I already own a DP to HDMI adapter and a DVI to HDMI cable, but I've heard that Eyefinity prefers all connections to be DVI. Would I have to buy a different set of adapters just to get Eyefinity to work properly?