Well, assuming you don't have a price limit... Here's something under 2 grand that might work well for you.

Case: Antec Nine Hundred (Generic, good cooling, up to you though)
Mobo: Asus Sabertooth P67 LGA 1155 (REV 3.0)
CPU: Intel Core i5-2500K (Would reccomend overclocking it)
CPU Cooler: Tuniq Tower 120 Extreme
RAM: 16GB (4x4GB) Corsair Vengeance DDR3-1600MHz (CMZ16GX3M4A1600C9)
GPU: Asus HD 7950 (HD7950-DC2T-3GD5)
PSU: SeaSonix X-850 Watt (SS-850KM)

Now I would HIGHLY recconmend using a Solid State Drive for your Master drive, they are about 8x faster than a hard drive and do not need to be defragmented, trust me, it's the best upgrade decision I've made to my computer in yeras.

SSD: Crucial M4 128GB (CT128M4SSD2) SO FAST!!!
HDD: Western Digital Green 750GB 7200RPM (WD7500AARX)

The HDD will basically be used as your slave drive, for storage, you want to keep your SSD as clean as possible, and store all torrents/movies/music on it. Save your SSD's 128GB for Games, and Windows.
The read speed of the SSD is ~500mb/s, the hard drive is around ~80mb/s.. It's insanely better.

I've used the listed RAM kit in about 4-5 computers I've built, amazing kit.
The Asus graphics card is amazing, the aftermarket cooler they have keeps the card EXTREMELY cool (good for overclocking)
And SeaSonic, while not as known as "Corsair" or "Antec", is actually the manufacturer of all Power Supplies except,
this is their own brand and they do a damn good job with their power supplies..
I didn't include Windows in this build, because most people have their "own means" of acquiring Windows, or they use
Ubuntu, it's up to you, it's easy to add later on.

The total for this computer ended up being $1582.92 + $138.77 tax, after shipping it ended up being 1860.65.
I used 90210 as the ZIP code for shipping, because I'm Canadian and that's the only American ZIP code I know.
I hope this helped, let me know if you have any questions in the future.

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Sorry for bothering you but i noticed your comment on the video ''Battlefield 3 HD 6770 1GB [ULTRA]'' .. Now i am wondering if you might be able to help me with some advice on a new pc to play Battlefield3 on a normal way. You would not believe how bad it is for me at this moment. (Yes it is my pc:P) If you are wondering what i got at this moment here it is: Intel Core 2 Duo E8600 (@3.33ghz) - Striker ll Formula - 4Gb DDR2 - HD4870. I know it is realy out dated, but i woud like some advice on my new pc. I hope you are able to give me some.

Hey mate I´ve read your comment on my track! thank you for your feedback!

greetings from Austria