Seth's same day gaming system build.
Stably runs Wow in max settings (Ultra mode) at 60+ FPS with GPU in 80°F range.

Case: $89.99 ♣
http://www.amazon.com/Antec-Nine-Hundred-Steel-Ultimate/dp/B000I5JHB0/ref=sr_1_1?ie=UTF8&qid=1317531748&sr=8-1

Motherboard: $266.99 ♣
http://www.superbiiz.com/detail.php?name=MB-FZ68PG3&c=FR&pid=cb802e3a2dbc8609dcf83f7da47dc175fbadbe58020b8a6c5d506da919c528be

 
CPU: $285  $332.47 ♣
$279 from Asia but don't have time to wait on delivery as it could take 2 weeks.  $285 shipped NIB from USA seller:
http://www.ebay.com/itm/Intel-Core-i7-2600K-3-4-GHz-Quad-Core-Processor-/110752511387?pt=CPUs&hash=item19c95d359b
eBay seller was a deadbeat, zero response to my 4 emails that I sent over an 8 day period.  As you can see from his auction, he said fast shipping & tracking, yet he provided neither.  Placed a 2nd order, this time from Amazon on Sunday, October 9th for one-day shipping (overnight delivery) on Tuesday, October 11th: http://www.amazon.com/Intel-i7-2600K-Processor-3-4GHz-LGA1155/dp/B004EBUXSA/ref=sr_1_1?ie=UTF8&qid=1318227630&sr=8-1

Memory: $49.99 ♣
http://www.newegg.com/Product/Product.aspx?Item=N82E16820104248

I have this kit in stock in original retail packaging, no scratches or scuffs. I paid $151.57, will sell for $49.99.

GPU: $175 by best offer ♣
GTX 560 Ti
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180731892333


SSD: $223.99 ♣
I don't recommend cutting corners here.  Though you could probably get by with one SSD for now, and use removable storage. Adding 2nd, 3rd drive and beyond can always be done.
http://www.ebay.com/itm/BRAND-NEW-SATA-3-Intel-Solid-State-Drive-510-Series-120-GB-SSDSC2MH120A2K5-/150666783656?pt=LH_DefaultDomain_0&hash=item231470aba8


PSU: $155 ♣
I did a bunch of research, hours, looking for a way to cut corners with a 650W power supply, and I didn't like the reviews of the cheaper models. The mid range 750W PSUs with good reviews were around $140s, then I came across this one for $224.47 on newegg or $210.95 on Amazon, but found awesome price on eBay for $155 new.  Is modular, reliable, 24-pin, matches motherboard colors, highest efficiency, perfect reviews, recent release product, and good price for what you get. 1120W power supply.  This way you can get the most powerful current and future single video card setups, such as the GTX 590.  Using GTX 590 in current build would be 759W draw at full load, but you wouldn't go with a 750W power supply that would fail. GTX 580 in this setup would pull 650W, but again, you wouldn't want 650W power supply, at full load, especially for an extended period, could result in overload, overheating, and again, failure.  This power supply should run smoothly under full load with most powerful GPU even at full load for extended period. Yet the reviews on this PSU are stellar, so I got it for the reliability and the future proofing.  Swapping out a PSU would also be a bitch, but since this one is modular, it will look nice because I can choose to use only the cables that are required, instead of having a bunch of extra cables tucked inside that don't serve a purpose.
http://www.ebay.com/itm/Enermax-Revolution-85-1050W-Power-Supply-SLI-/190583780115?pt=PCA_UPS&hash=item2c5fadb313

 
DVD burner: $22.90 ♣
http://www.ebay.com/itm/NEW-LG-Black-SATA-Super-Multi-Internal-22X-DVD-Rewriter-GH22NS70-/130579693159?pt=PCC_Drives_Storage_Internal&hash=item1e6727fe67

Thermal grease: $7.97 ♣
http://www.ebay.com/itm/Zalman-ZM-STG2-Super-Thermal-Compound-Paste-ZMSTG2-NEW-/280575182010?pt=LH_DefaultDomain_0&hash=item41539584ba

 
OS: $93.49 ♣
Windows 7 Home Premium 64-bit
http://www.ebay.com/itm/310216331063?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

MS Office Professional 2010: $111.75
http://www.ebay.com/itm/Microsoft-Office-Professional-2010-Academic-Box-NEW-/250849006635?pt=LH_DefaultDomain_0&hash=item3a67c4142b

Miscellaneous: $5
Red SATA interface cable for SSD $2.50
Modular to SATA adapter for SSD $2.50

Packing material: $16.57
Double box packing for computer from UPS Store with custom Styrofoam fitting to protect all sides.


Recommended gear: $2,019.15
Budget build settling for downgrades: $1,439.36

You could certainly cut more corners and get the price down to $1000.  We could even build a 2nd generation i5 system with all NEW parts for < $250.  You can downgrade wherever you like though, totally your call.  Just keep in mind that if your goal is to play the latest games in ultra mode with high frame rates, reliability, and be as future proof as possible, then that would be the recommended build.

Similar Dell system build would be $3,043 before tax and assuming free shipping, or $3,324.47 if ordering from Tennessee.  Keep in mind that this is with lesser PSU, unknown motherboard and SSD make/model, and is barebones configuration (no mouse, keyboard, misc add-ons or software, or display) but with GTX 580 instead of 570 as they didn't offer 570.  I'm 99% certain that Dell would use inferior motherboard, SSDs, PSU, and memory brand, otherwise they would be disclosing the make/model if they were using the latest and greatest in the build.  Hypothetically, if they did use the very best brand components, their markup is a solid 50% above retail cost of hardware, and of course they get better pricing than retail because they buy in volume so their margin is more like 60%+.  Then you pay state sales tax on top of that... Configure for yourself to see:
http://configure.us.dell.com/dellstore/config.aspx?oc=dpcwsw1e&c=us&l=en&s=dhs&cs=19&model_id=alienware-aurora-r3

Or, a step up from Dell would be from Origin PC (founders of Alienware before they sold to Dell).  They would charge $3,376 + $107.17 (for cheapest shipping) before tax (if applicable) to Tennessee for a near exact build except definitely an inferior motherboard, same model SSDs, same GTX 570, more memory (but that's only $50 more retail, yet downgrade performance wise), yet includes t-shirt, all for $3483.17 (before tax, if any).

For comparison, here's my system build from last year that I'm currently using, but this was for a silent workstation build & not for gaming:
http://www.neo-geo.com/personal/i5-fanless/build.html