We also have additional suggestions for our Double-Stuff build.

Processor
This is an expensive trade up, but there are tangible advantages to selecting the Core 2 Extreme QX9650. For one, this processor takes all four of its 45nm Penryn cores up to 3GHz, making it as fast as the Core 2 Duo E8400 in applications not designed to use more than two cores—and much, much faster in those that do. We were able to push our QX9650 up to a whopping 3.67GHz, suggesting this processor has healthy overclocking headroom. Your own mileage may vary, of course, but the QX9650 is definitely a substantial upgrade for those with deeper pockets.

Motherboard
Gigabyte's GA-X48-DQ6 motherboard is based on Intel's top-of-the-line X48 chipset, which supports second-generation PCI Express connectivity and 1600MHz front-side bus speeds. All the trimmings one would expect from a high-end motherboard are included, such as eight 300MB/s SATA ports with RAID support, dual GigE controllers, passive chipset and voltage circuitry cooling, digital audio outputs, Firewire, and eSATA connectivity. The DQ6's BIOS is loaded with overclocking and tweaking options, too. We haven't tried overclocking this particular model ourselves, but we managed to push its DDR3 twin, the X48T-DQ6, to a 500MHz front-side bus. The X48-DQ6's near-identical, X38-based predecessor also had no problems running a 500MHz FSB in our labs. How's that for consistency?

Graphics cards
Dual graphics cards are nice, but some folks don't want to deal with compatibility hassles or the additional space required. Some may also want to use the aforementioned X48 board, which lacks support for Nvidia's SLI multi-GPU scheme. For such users, AMD's Radeon HD 3870 X2 is a decent alternative to our two GeForce 9800 GTXs. The X2 won't be quite as fast, but its two RV670 graphics processors more than hold their own in the latest games at the highest resolutions. You can check out detailed performance numbers here. Even more importantly for a system of this caliber, AMD's drivers allow the X2 to operate seamlessly with dual displays, with no need to enable or disable multi-GPU mode via the control panel. That's a huge improvement over SLI, which clumsily requires manual switching from dual-GPU mode to multi-display mode.

Storage
The SpinPoint F1 1TB's apparent issues with nForce storage controllers shouldn't faze our alternative configuration's X48-based motherboard, so the Samsung drive gets the nod here. If you're looking to maximize storage capacity without sacrificing noise levels or spindle speed, the F1 is your best bet. Thanks to its high-capacity 334GB platters, this drive delivers the fastest sequential transfer rates we've ever seen from a 7,200RPM hard drive.

Sound
The Xonar D2 is great for audiophiles, but the Auzentech X-Fi Prelude has a few extras for gamers and multimedia enthusiasts with equally deep pockets. Auzentech has combined a Creative X-Fi chip, which offers hardware acceleration for positional audio and native EAX Advanced HD 5.0 support, with the audio quality and features one might expect from high-end sound card. What's more, the Prelude's ability to encode Dolby Digital Live streams in real time is unique among X-Fi cards. The Prelude earned a TR Recommended award when we reviewed it, too.