Well, I haven't read any of the earlier posts in this thread, so please excuse me if I restate anything.
Cyberpower is overall a very good vendor, and I have been happy with the old system I bought from them a feww years back(I use a new PC, now). In my opion,
AVA and
Vigor are two of the best on the market, when it comes to high-performance systems. My current PC is a Vigor, actually.
As for the RAID setup,RAID-1 is best security, though if you can afford three drives, and the vendor offers RAID-5, then you not only get security, but a slight performance increase is well. For the Quad-Core CPU, AMD just released its Phenom X4 quad-core series last week, though an Intel Core 2 Quad or Extreme is better, unless you have a tight budget fo this rig.
Have you considered buying a worstation or server, since you are hosting a website, from what I understand? AMD offers quad-core Opteron for servers, and Intel Quad-Core Xeon, though Xeons are very expensive. if it is a server/worstation that you're looking for, then
Xi is also good.
As for the RAM, then I reccomend either Mushkin or OCZ, maybe Corsair, too. If this is truly going to be really high-end, and only if you can afford it, then DDR3 RAM is extremely good as far as performance goes. If DDR2 RAM is prefered, then the best you can buy is probably Corsair Dominator RAM. Do note that special motherboards are reqiured to have DDR3 RAM.
A few reccomendations on your graphics-card(s)(GPU). Good Nvidia makers are EVGA and XFX. The best bang-for-the-buck card out there is the 8800GT, it sells for about $250 USD, and has performance just under a $525 8800GTX.
Make sure that you have a powerful enough Power-supply(PSU) to support all of your components. for two 500GBs hard-disks, 4GB of high-end RAM,
and a quad-core CPU, anywhere from 700watts to a kilowatt should do, depending on your other components. Also equally important is that you get a good motherboard(mobo). If you want SLI, make sure you have an SLI supporting board with 680i SLI. My personal reccomendations would eithe be an MSI P6N Diamond nforce 680i, or an Asus P5N32-E nforce 680i. The best board out ther is the Asus Striker Extreme, but its overclockability is limited.
Core 2 Quad Q6700 @ 3.44GHz | Asetek Liquid CPU Cooling | 2 x eVGA SSC GeForce 8800GTS G92 |512MB (SLi) | 2 x 150GB 10,000-rpm Western Dig. HDD RAID-0 array | MSI P6N Platinum 680i | 1.0KW PC Power & Cooling PSU | Lite-On DVD +/- RW