1300-1600$
thats the budget for a high end pc without going overboard to the i7X and other things that you won't need for just gaming.
I7 CPU 930 now and 950 in august when its price drop, the 6core stuff is way over priced.
For a Mobo you won't need anything special but the EVGA FTW3 and Gigabyte UD5 and even an Asus Premium are whats good and decently priced though the 1st two support USB3/SATA3 no need to go past that.
For ram the staple is DDR3 6GB (3 Dimms) @1333 to 1600 any more is just throwing away money if you're not a serious overclocker.
Now the Graphics card, this is an Nvidia game so I'd lean toward their cards at the moment the most logical approach is a GTX480 and I would Get a Geild Icy vision cooler for it for long play, its not as hot as people claim but its still hot, the cooler drops that 20c and that's amazing.
Then there's the GTX470 which is a great card with no flaws, which you can SLI if you want and it scales and overclocks like a champion.
GTX465 is trash
GTX460 is Nvidia's new 8800GT, the finally pulled it off, its at a great price and is amazing in SLI if you're going with this card you'll want two and no less than that and it'll perform up there with the HD5970 for half the price. GTX460 in SLI is one heck of a deal.
Now the DVD rom, just buy anything with x22+ and you're set
Storage
The staple is a WD Caviar blue 500GB you can go further by adding a 1 or 2 TB Green drive to store your things (looking at you, Naruto fans) if you're going further then you'll walk into SSD territories and they cost too much so right now a 40-90GB SSD for windows is as far as any sane person is willing to go, personally I'd go with a Vertex or a Vertex II from OCZ.
Now the PSU I wouldn't go under 750w and it has to be a good company, the GTX460 in SLI will need around that much the bigger cards however... you'll want 1000w and above.
Now this junk needs a case and a Full tower is a good idea, there's alot of those but my favorites are:
Cooler Master
HAF 932
HAF X
Cosmos S
Antec
1200
Thermaltake
Armor +
Spedo Advanced
With my most favorite being the HAF X
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Being at work with no youtube is inspiring.