I chose Intel Core 2 Quad Q9300. It cost ~215€. I wanted 4-core CPU with both good performance and low power consumption. At that time, Windows 7 were introduced with their XP-mode, so I wanted my new CPU to handle hardware virtualization. Right now, this CPU still handle every game I want to play, 3D model I want to render or archive I want to compress (But I am already looking forward for Sandy Bridge, because there is never enough performance!).CPU Cooler
I hate loud stock "cooler" which is added with processor. I wanted the best cooler with the best fan, so I chose Thermalright Ultra-120 eXtreme (for ~16€) 
with Noctua NF-S12-1200 (for ~14.50€). There where slightly better coolers with much more weight, but I did not want my motherboard to be ripped with so much weight. I am also satisfied with noise and cooling abilities. Because only thing I can hear in idle is Graphic Card.
Gigabyte GeForce 98000 GX2. To be honest, I hate this card. This massive card has two cores, so it has pretty good performance, but it produces a lot of heat. Thats why it is loud even in idle! God help me, when I want to play games. It is extremely loud! It requires 2x8pin additional power connectors and it is so long! It hardly fits into middle tower case. Okey, but I should be happy with performance, shouldn't I? No I am not. Why? Microshuttering. Games keep shutter even on high framerate. It is so annoying! To sum up: Hungry monster. Very powerful, but hungry all the time. For beautiful 416€!Motherboard
Very expensive (~271€) but equipped with lot of good stuff. Asus P5E3 Premium/Wifi-AP. Intel X48, 3xPCIe x16, 1xPCIe, 2xPCI, 4xDDR3, 6xSATA (not enough xD), 2xGb Lan, 2xWifi. I am happy with my choice. Good layout, beautiful (if it can be said about piece of hardware) build-on cooler and (as a bonus) 2 wifi antennas. "Only" 271€.
Case
About the case... Well, I want it to have I/O connectors on the top, dust filter and enough positions for drives and disks. I wanted (but did not required) eSATA connector on the top too. So I chose Enermax ECA 3050-BS Chakra for ~66€. Now I can see, that chakra of this case is very weak ;-) Why? Enermax Charka is made of thin low-quality material. Tool-less green plastic parts can be easily broken. Right now I am saving for new better quality case...
System Harddrive
2 years ago there where no cheap SSD drives so I wanted the best of traditional HDDs. I am not fan of 10.000rpm drives because of noise and vibrations. So I looked through a lot of reviews and benchmarks and chose WD Caviar Blue 3.5" 640GB WD6400AAKS. Response time, copying times and other tasks are good. It cost ~79€. I was really worried about the noise so I bought HDD cooler and silencer.
Silentmaxx HD. I can not hear heads seeking or plattes running. It is awesome noise reducer. But it was little bit expensive: ~38.50€.
