I'm looking to upgrade my graphics card. Currently I have a GTX 570 that has lasted me a few years just fine. I have a single display, 30" 2560x1600 resolution. Lately I've been playing around with skyrim mods and far cry 3 and it's become apparent I need more power handle these games at this resolution. I'm looking to have most if not all settings maxed on these games. I realize graphics are pay to play so I'm willing to put in a good bit of cash (probably $700 max), but not so much where I'd just go and buy Nvidia's 690. I have a large case as well as motherboard that supports both SLI and Crossfire (Sabertooth x58) so I would be open to multi GPU configurations. If anyone can give advice that'd be great!
Multi gpu configurations are known to cause problems.
Get a single HD7970 GHz or a GTX 680 and you'll be fine. This cards will easily be able to play all your games as max/high for about a year or two.
But as it already February you should probably wait for the AMD HD8000 series to be released and buy a high end card from that series.