And remember you can get a PC that runs FH2 on max and Crysis very high for about 400$.
Everything else is just sbling and costs too much money atm.
FH2 at 1024x768 and Crysis on medium settings maybe.
Either way, it doesn't sound like you want any low end stuff.
Build your own computer. Following the instructions its as easy as building lego. For 50$ you can even select your own parts and have most computer stores put it together for you. If you buy something from Dell or Alienware, you're going to be paying them 200 to 400$ more than for the parts, atleast with such high end computers. You can instead pay most computer parts websites 50$ to put parts which you choose together. Computer companies also force you to buy windows vista, easily adding a couple hundred dollars to the price while most people have an old copy of Windows XP lying around, which runs games 10x better.
I don't know much about CPUs atm, but these aren't as important choice wise as graphic cards. Get one that fits your budget.
Since you're obviously going high end, get two ATI 4890s or an nvidia GTX 295. If there's anything to use your money on, its the graphics card.
DDR3 ram hasn't shown to be very superior to DDR2, yet. It'll be the standard in the future. Since you don't want to cut any corners on the budget, get atleast 4GB of this. At the moment, nothing will use more than this unless you're running 20 copies of 3ds max at once. You can easily upgrade later if its needed.
For a power supply, make sure it fits the minimum requirements of the graphic card(s) (google it).
Also important is screen and audio. Without these, putting in money for a fast computer will be pointless.
Again, don't cut corners here. Now these vary a lot, some people don't like input lag and prefer CRTs, while most don't even notice input lag and want a good sized LCD. Personally, I'd recommend a Dell or Samsung 24" screen, with 1920x1200 resolution. These have a good comprimise between input lag and resolution. Input lag generally does not go above 30 - 40ms, while allowing you the competetive edge when it comes to resolution, thus detail. For audio I won't give any suggestions, except for get a soundcard that fits your budget.
A motherboard is usually the last thing you choose. Unless you're into overclocking and the like, which I don't think you are, get one that fits the parts you choose. Simple as that.
For computer cases, mice, keyboards, DVD rom/bluray stations etc. etc. I won't give any advice. These are as simple as it gets. Also, don't buy a 100$ mouse and not a mousepad. Mousepads are very important, while being relatively cheap compared to most other stuff. On my current Q-pad, I can play just fine with a ball mouse if needed.
The above will probably not run you above 1500 - 2000$. Hope this helps.
EDIT: I almost forgot about harddrives!
Harddrives are in a changing market at the moment. The old style harddrives are being replaced by Solid-State-Disks (SSD). SSD disks, while having much lower capicity, are MANY times faster. Most people in the high end business have one or two of these, together with a traditional harddrive. They use the SSDs first for windows, then for games if they have room, and save video/audio/pictures on the traditional harddrive.
If you decide to go with a traditional harddrive, since SSD disks are still very pricey, I suggest to go RAID. RAID is basically hooking up two harddrives, writing half of each file onto each harddrive. This makes writing and reading from the harddrives TWICE as fast. Both traditional harddrives and SSD disks can use this setup.
