For a purely gaming rig, you don't need an i7 or $2400. You can get a killer system for a grand less.
Also we need more information, can you fill out this form. It will mean we arent flying blind to what you need and want.
http://www.tomshardware.com/forum/353572-31-build-upgrade-advice
But heres my crack at it from I know so far.
CPU: i5-3570k. $230
http://www.newegg.com/Product/Product.aspx?Item=N82E16819116504
For gaming, an i5 is all you need. Its a waste to get an i7 as its hyperthreading technology just isn't utilized in games.
Motherboard: AsRock Z77 Extreme4. $135
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157293
Very good motherboard, have it personally and nothing but praise. Heres some reviews of it.
http://www.vortez.net/articles_pages/asrock_z77_extreme4_review,1.html
http://www.tomshardware.com/reviews/z77-express-ivy-bridge-benchmark,3254-2.html (it tied first for mobo's under $160)
RAM: G.Skill Ares 8GB (2x4GB) 1600mhz CL9 1.5v. $44
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231544
Fairly standard kit of low profile RAM
PSU: Corsair HX750, semi-modular, 80+ Silver. $145
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139010
Good brand, modular where it needs to be, fairly good efficiency. Can upgrade to Gold efficiency through some Newegg deal, not sure how to do that though.
GPU: Gigabyte GTX670. $400
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125423
If multiple monitor gaming is a possibility, you should consider the HD7970. But on a single screen, this will do just fine.
Gigabyte, ASUS, MSI, Sapphire, Zotac are all good manufacturers to pick from. I avoid EVGA because they use a reference design on their cooling.
HDD: Seagate Barracuda 1TB 7200RPM. $90
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840
Fast and inexpensive compared to Caviar Blacks,come with less warranty, but a HDD will fail within three months or never. Get more/bigger drives if you need the storage.
SSD: OCZ Vertex 4 128GB. $115
http://www.newegg.com/Product/Product.aspx?Item=N82E16820227791
Trading blows with others for the fastest SSD on the market, and if OCZ keep pumping out updates, will only get faster.
CPU Cooler: Coolermaster Hyper 212 EVO. $36
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103099
The go to budget air cooler. Will easily support moderate overclocks on the 3570k.
Case choice is largely personal, you have to like the look of it after all. Here are some good choices, but feel free to find your own. Just make sure to research it first though.
Coolermaster HAF-XM. $130
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119257
Its a "mid-tower" that's only a few inches smaller than a full tower. Plenty of space and amazing features (My personal choice).
Corsair 400R. $140
Subdued aesthetic, great features. Wont find much wrong with the case.
http://www.newegg.com/Product/Product.aspx?Item=N82E16811139009
NZXT Phantom, various colours. $120
Also a good choice.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=100006644&isNodeId=1&Description=NZXT+Phantom&x=0&y=0
Total: $1335 (Corsair Case picked)
That rig can overclock and has the potential for dual graphics cards. It will play the latest games at max settings.