I just finished building my new computer.
Specs:
i7-2600k Quad Core @3.4 Ghz
ATI Radeon HD 6950 (Dont cheap out like the above poster said...)
2 x 4 GB Corsair Vengeance DDR3 RAM
AsRock z68 extreme3 gen3 motherboard
Corsair 750W PSU
Lite-On DVD Writer
1 TB Western Digital Black Caviar HDD (7200 RPM is what you want)
Thermaltake Level 10 GT case

One major tip I would give for saving money is MAKE SURE you buy your Windows 7 WITH your purchase of motherboard. You will end up saving about 100 dollars if you buy the OEM version of Windows 7, which Microsoft limits to computer-builders only.

Putting it together is not a hassle at all, there are some parts that are frustrating but give yourself two hours to work through it and you will be fine