Gaming PC

[mike3]

need help with choosing from these parts :

mobo: ASRock Z77 Extreme4 Socket 1155 Motherboard
OR Gigabyte GA-Z77X-UD3H Socket 1155 Motherboard

CPU: Intel® Core™ i5-3570K Ivy Bridge 3.4GHz 6MB Cache Desktop Processor

RAM: CORSAIR Vengeance 8GB (2 x 4GB) DDR3 1600 CL9 Dual Channel Memory Kit
OR G.skill Ripjaws-X 8GB (2 x 4GB) DDR3 1600 CL9 1.5v Dual Channel Memory Kit

GPU: Gigabyte AMD Radeon HD 7970 OC 3GB

HDD: Seagate Barracuda ST1000DM003 1TB 7200 SATA 6Gb/s HDD

PSU: XFX ProSeries 650W PSU 80 plus Bronze
OR CORSAIR Enthusiast Series TX650 V2 80 PLUS Bronze PSU
"someone told me that Antec VP550 550W PSU is enough"

not sure about the case ,, i was going for phantom 410 but it is out of stock ,, i think CM storm enforcer is ok

 

[C12Friedman]

If you like the style of the Phantom case, I'd suggest holding out until it is in stock - it is unique enough that a substitute just won't be the same (IMO).
On your other parts choices, from what I have read, the ASRock is a better overclocking board than the Gigabyte board.
Ram, either/or since the specs are the same
I will recommend the XFX ProSeries (made by SeaSonic) 650W, reviewed here http://www.hardwaresecrets.com/article/XFX-PRO-650-W-Core-Edition-Power-Supply-Review/1165/10 (linked to conclusion page). Note that the Corsair TX650 V2 is also made by SeaSonic but I could find no reviews for that unit - I'll stick with the one that's reviewed (very similar specs though so performance should be about equal I would think).
That's really all I got

 

[Deemo13]

If you are actually going to overclock, be sure to get a CPU cooler.

 

[zander1983]

Mobo = quality wise the GB is probably better. I personally prefer ASUS boards
RAM = which ever looks the nicest or fits with your colour scheme if you are going that route
PSU = Corsair & XFX are made by Seasonic. Any of this 3 in 650w flavour should be fine. Check modular cables etc to see which one will fit you best.
CASE= don't rush it, that is the main thing that will make or break your pc. Wait and and get the case you want.