I currently have two EVGA GTX 550 Tis overclocked to 1000 MHz Core and 2613MHz Memory (stable, max temps are 70C gaming, 80C benching).
I bought the 550 Tis several months apart for dirt cheap, so don't rail on me for buying weak.
Anywho, I'm a moderate gamer - Battlefield 3 is the most intensive game I have at the moment, and I run that at a relatively stable 60 FPS (avg 58) on the below settings:
Resolution: 1080p @ 60Hz
Texture Quality: High
Shadow Quality: Ultra
Effects Quality: Ultra
Mesh Quality: Ultra
Terrain Quality: Ultra
Terrain Decoration: Ultra
AA Deferred: Off
AA Post: Medium
Motion Blur: Off (personal preference more than anything else)
Anisotropic Filter: 16x
Ambient Occlusion: SSAO
CPU is a i5-3570K under a Hyper 212+ overclocked to 4.1GHz at stock vcore (will upgrade to a Zalman LQ320 soon, but that's another story).
Motherboard is an ASUS P8Z77-V LK
Case is a Fractal Design Define R4 with all fan ports filled and HDD cage removed (max card length: 16.9 in)
PSU is a 600W Thermaltake TR2
My other question is, will the performance boost I get with a GTX 670 (I intend to overclock as much as possible) over two maxed out 550 Tis be worth the ~$400 investment? My friend and I compared MSI Kombustor benches, and my GTX 550 Tis (P3487) come within striking distance of his overclocked GTX 680 (P3822). Of course, benches are benches, and he gets significantly higher real-life performance than I do.