I recently (last few weeks) upgraded my main computer and have been super happy with it.
I have an existing Antec server sized case I always use, love it. I just installed new parts which are:
- Corsair 850 watt power supply
- Asus Premium P6x58D board (supports USB 3 and SATA 2, 64 bit)
- 6GB OCZ memory (OCZ3G1600LV6GK)
- Intel i7 Bloomfield 2.8ghz quad core 1366
- Windows 7 64 bit (OEM version)
- Western Digital Caviar Black 1.5TB (want to get another to mirror RAID them)
- ATI 5870 1gb*
* I was going to keep my old graphics card but the machine I was moving parts down into, when I moved my old motherboard to it the older graphics cards was AGP, and the board didn't support it. Was a good excuse to get a new graphics card! Haha. I lucked out big time, a friend of mine had an extra ATI 5870 graphics card so I bought that from him.
I've been VERY happy with it, it's super fast, plays games with ease. My main game is Battlefield Bad Company 2 and I have all my settings in graphics maxed, runs like a dream (and looks amazing).
I got all my stuff from Newegg.com - best overall prices I tend to find.