Old build looking to upgrade

Hello all,
So it's been just a touch over 2 years and this build has given me a great gaming experience. Hands down the best PC I've ever owned. I've been out of the loop for a bit and was wondering is it even worth upgrading at this point and if it was what components? Video Card I was thinking but is my mobo compatible with a new video card where it would actually be worth it. Any feedback would be greatly appreciated. Thx
-JVoye
Here is my build-

Specifications:
Chassis Model: Special Deal Hot Seller - Cooler Master 942 HAF X
Exterior Finish: - Standard Factory Finish
Trim Accents: - Standard Factory Finish
Processor: Intel Core i7 2600K 3.40GHz (Unlocked CPU for Extreme Overclocking) (Quad Core)
Motherboard: ASUS P8P67 Deluxe (Intel P67 Chipset) (New & Improved B3 Revision Without SATA 3G Issue)
System Memory: 8GB DDR3 1600MHz Digital Storm Certified Performance Series (Highly Recommended) (Hand Tested)
Power Supply: 1050W Corsair Pro Silver 1050HX (Dual/Triple/Quad SLI Compatible)
Expansion Bay: - No Thanks
Hard Drive Set 1: Operating System: 1x (120GB Solid State (By: Intel) (Model: 320 Series)
Set 1 Raid Options: - No Thanks
Hard Drive Set 2: Multimedia\Data: 1x (1TB Hitachi/Seagate (7200 RPM) (32MB Cache)
Hard Drive Set 3: Backup\Misc.: - No Thanks
Optical Drive 1: DVD-R/RW/CD-R/RW (DVD Writer 24x / CD-Writer 48x)
Optical Drive 2: - No Thanks
Internet Access: High Speed Network Port (Supports High-Speed Cable / DSL / Network Connections)
Video Card: 2x SLI Dual (NVIDIA GeForce GTX 570 2.5GB (PhysX) (EVGA 025-P3-1579-AR) <b></b>
Add-on Card: - No Thanks
Sound Card: Integrated Motherboard Audio
Extreme Cooling: AIR: Stage 2: Corsair A70 Dual 120mm Fans High Performance Cooler
H20 Tube Color:- Not Applicable, I do not have a FrostChill or Sub-Zero LCS Cooling System Selected
Chassis Airflow: Standard Factory Chassis Fans
Internal Lighting: Internal Chassis Lighting System (Red) <b></b>
Enhancements: - No Thanks
Chassis Mods: - No Thanks
Noise Reduction: - No Thanks
LaserMark: - No Thanks
Boost Processor: Stage 2: Overclock CPU 4.5GHz to 4.8GHz (Requires Pro or Deluxe Series Motherboard)
Boost Video Card: - No Thanks, Please do not overclock my video card(s)
Boost Memory: - No Thanks, Please do not overclock my memory
Boost OS: - No Thanks, Please do not tweak the services on the operating system
Windows OS: Microsoft Windows 7 Professional (64-Bit Edition) <b></b>
Recovery Tools: Windows Recovery Toolkit (Bundled with Windows 7 CD)
Virus Protection: - No Thanks
Office: - No Thanks
Install/Test Game: - No Thanks
Display: - No Thanks
Surge Shield: - No Thanks
Speakers: - No Thanks
Keyboard: - No Thanks
Mouse: - No Thanks
External Storage: - No Thanks
Exclusive T-Shirt: FREE: Digital Storm T-Shirt - Black (Medium)
Priority Build: - No Thanks, Ship Within 5-15 Business Days After Order Is Successfully Processed
Warranty: Life-time Expert Customer Care with 3 Year Limited Warranty

If you're gaming on a 1980x1080 monitor then I would save your money for now.   Still very good gaming.    If you are seeing issues then a sli 770 or sli 780 like suggested would be my choice.   A single 780 is about the same gaming as sli 570 so another sli setup is needed for it to be worth the money.

The new cards are Pcie 3.0 and your mobo/cpu are Pcie 2.0 but it's backward compatible with little performance loss if any.

The rest looks great. I have the A70 cooler and love it.   

Good luck.

bp22 already mentioned that a single 780 would be about equal to what you have so a single 770 would offer less performance overall but better when games only utilize a single card. You would need to go SLI again to better the performance of what you current setup already offers. The mobo & PSU are fine for the upgrade...

On the anandtech site, you could use the 590 card for comparison since your SLI 570s are very close in performance to the 590. My PC is pretty close to yours (a year older) and I was happy with installing a bigger SSD that I plan to move to my next Digital Storm PC next year...