Points:
1) The 1090T will definitely BOTTLENECK the GTX670 in quite a few games. With the amount of money you are spending the i5-3570K would be the best choice. Some games won't be bottlenecked, but some will be severely. Here's an example of how it works (this benchmark doesn't show the 1090T or the 3570K it's just an example):
http://pinnaclegameprofiler.com/forum/showthread.php?13319-Starcraft-2-CPU-scaling-benchmarks
I calculated up to a 40% difference roughly in some CPU-dependent games when comparing the 1090T and 3570K (and again, anybody can grab a benchmark for some games that shows minimal difference). Obviously the 1090T is cheaper but when comparing the TOTAL COST of ownership it's not a great value. Some of the newer AMD CPU's are much better value but the i5-3570K still wins overall but you can't pick and choose your benchmarks like some people do. It's the worst-case, CPU-dependent games you need to look at.
**CPU bottlenecking can also show up as more frequent MINIMUM frame rates causing periodic stuttering even when you can maintain 60FPS most of the time. This primarily has to do with single-core performance which the i5-3570K excels at.
2) If you get the i5-3570K you'll want a compatible Z77 1155 motherboard (Asus, Gigabyte, Asrock or MSI). Asrock seems to have good value.
3) EVGA GTX 670 FTW cards don't have the optimal cooling setup. There's also quite a bit of value with some of the AMD cards (two free games). After a lot of research, here's a really awesome card:
http://www.ncix.com/products/?sku=68755&vpn=HD7970-DC2-3GD5&manufacture=ASUS
*Note the two free games (digital download). This card should be overclocked to 1000MHz. It's a 3-slot card which will give performance identical to a GHz version when overclocked and still run quieter. It's $440 and will be better than a GTX670. I don't consider PHYSX a big deal as it's often just a little eye candy that may take a big performance hit. Adaptive VSYNC is nice but not a deal-breaker and it's also driver-based so AMD will likely add it soon.
And here's the review:
http://www.guru3d.com/articles_pages/asus_radeon_hd_7970_directcu_ii_review,24.html
4) Windows version:
- Unless you really need the Ultimate version, it's more expensive so be sure it's what you require.
- Windows 8 is superior to Windows 7 in many ways and the new interface issue is solved by using START8 from Stardock ($5). Windows 8 (get 64-bit OEM) is:
a) faster to boot
b) more secure
c) more reliable
d) has better memory management
e) has better SSD support
f) improved Windows Explorer
*There's no gaming difference but the guts of it are rock solid and improved. Compatibility issues are few. The Pros simply outweigh the Cons.