Since you only games on 1 monitor, I would just get a single GTX 680 preoverclocked for now, you can always buy a 2nd one and SLI later on if needed, even though I highly doubt you will need it any time soon. Or if you want to, buy 2 of the GTX 670 now and enjoy the fps. The built below is capable of powering 2 GTX 680.
Regarding CPU: Unless you do professional works such as video editting, video encoding/decoding etc there is simply no need for LGA 2011 ie Sandy Bridge E. Ivy Bridge i5 3570k gives you idential performance as the i7 3770k and the much more expensive i7 3930k and the 1000 bucks i7 3960x in gaming. If you feel like you will be doing some video editting, get the i7 3770k instead of the i5 3570k. Save the rest of the money to get a good video card, SSD and high end PSU and mainboard.
Cases are very personal, choose any other cases that you prefer that is not listed. Just make sure they are designed for cable management and have good airflow. Any of the case listed above have excellent air flow and are designed with cable management in mind.
For mainboard, Asus or Gigabyte are usually first choice for those who have the budget due to high quality. For those who are on low budget, they usually choose a cheaper alternative such as Asrock and MSI, not that the motherboards made by these 2 brands are of lesser quality or anything, it's just that they are newer to the market and thus they need to compete based on price. Also, when choosing motherboard, make sure you choose the one that has at least 12 phases power to ensure overclocking stabilities of the CPU. The Asus P8Z77V-Pro (linked above) has 16 phases power.
Video card: EVGA GTX 670 FTW $419.99 - $10 MIR = $409.99 -- Buy 2 of these if you feel like SLI is a must now. GTX 680 is currently out of stock and being sold by 3rd parties for more than 600 bucks each so its not worth it to get it over preoverclocked GTX 670, which gives you identical performance if not more for 200 bucks less. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
For Power supply, the Seasonic X series are among the top tier in terms of quality PSU, the Corsair AX linked above is a rebranded Seasonic X and OCZ ZX is also a very good quality PSU as well but cheaper than the other 2. Of course there are other cheaper PSU like the Corsair TX V2, XFX Core Edition etc that can also deliver the advertised power with minimum ripple and noise, but they are not made of highest quality components hence they are cheaper. So go with your judgement which one you prefer.
There are also good low budget coolers out there such as Hyper Evo, Hyper 612 etc.. but since you have a good budget why not aim for a good coolers to keep temperature down, considering Ivy runs hot when overclocking.
Needless to say the RASA kit has highest cooling performance but setup can be tricky especially for 1st timer, the radiator needs to be placed externally. Corsair H100 is a full closed loop water cooling kit and requires no maintenance, installation is similar to any air coolers and has higher performance than any air cooler on the market. Nocture DH14 is the cheapest of the 3 and performance is also not as good as the other 2 but should be close to the corsair H100.
Here is the review of CPU cooling performance that has all 3 of the coolers listed above. Note: Corsair H100 in the review uses only 2 fans push configuration, to maximize performance of the Corsair H100, a push/pull configuration with 2 fans on top and 2 fans on the bottom should be used. Replace stock fans with Cougar fans to eliminate noise for those who are sensitive. http://www.overclock3d.net/reviews/cases_cooling/corsai...
System Usage from Most to Least Important: Gaming only.
Parts Not Required: keyboard, mouse, monitor, speakers
Preferred Website(s) for Parts: newegg
Parts Preferences: Intel for processor
SLI or Crossfire: Yes
Monitor Resolution: 1920x1080
Additional Comments: Quiet, cool and powerful
A single GTX 670 will max every game out at 1920x1080p. There is no reason to spend 3k just to game at 1080p. You can max every game out with a 1500$ budget. Now if I had 3k I would get an Nvidia Surround setup which needs much more graphics power and you can justify 2 GTX 680's in that build.
You first want to set yourself up with three good monitors. The Dell U2412M is a fantastic monitor that is deemed recommended buy by the Tom's Hardware site.
Dell U2412M- http://www.newegg.com/Product/Product.aspx?Item=N82E168...x3=930$
These monitors will last you many builds and they are something to build around.
Now with 2070$ left here is what should be in the tower-
Now sure we've gone over your budget a bit, but you did say $3000 PLUS. Which brings us to our next step:
3) Select some random lucky guy who posts a System thread who has a $500 budget and needs Windows and a Monitor in addition to a rig and just send him your old 1920x1080 monitor.
Here's what you've now accomplished:
- You've got a sweet rig, the envy of the Tom's Hardware community.
- It's got plenty of room for future upgrading, and will last your for, well, a while.
- You've got an awesome monitor and all of your non-tech savvy friends will marvel at how thin and big it is.
- You'll make some lucky blokes day/year/decade providing him with HD quality Diablo 3.
- You become an instant legend around these parts
Seems like a win, win, win, win, win situation to me.