I'm from Germany, so the prices are all in €. I put the prices in $ under the € prices. Hardware prices seem to be rather high in Germany.
I'd be thankful for all suggestions on how to improve the performance of this Computer or reduce the costs without major performance losses. Its main purpose should be gaming and it should also be possible to upgrade the prozessor or video card(or SLI/crossfire) in a year or three when it becomes necessary. And D0 stepping would be a nice feature for future overclocking. I know there are 2 i7-920, one with D0 and one with C0. So maybe I should get another cpu if I can't be sure to get a 920 with D0.
Somehow when I add all individual prices in $ together i get $1789.02 but when I convert the total € price to $ I get $1974.21.
Welcome to the forum.
I would look for a power supply from corsair, antec, pc power and cooling, or seasonic, if available. You'll want one in the 750W range (with 4 PCI-e connectors) for future crossfire.
Also, get a cheaper motherboard such as the Asus P6T.
If that hard drive is from the 7200.11 family, avoid it. Get a Spinpoint F3 or Caviar Black instead.