Here comes the trouble: RAM: I'll be buying G. SKILL or Corsair 4Gb or 8Gb, I am confused. GPU: I'll be buying a GTX 560 Ti but can't decide which brand. I heard GIGABYTE's GTX 560 Ti SOC is amazing but unstable; I dunno if that's true. Maybe, an ASUS GTX 560 Ti Direct CU II is good. PSU: The local dealer has Gigabyte PSU's, if someone can recommend a good one I'll be thankful. Any other recommendation would be great! Case: This one depends mainly on the local dealer. I saw some GIGABYTE cases at the store so, if someone can recommend a good one, that'll be nice. CPU cooler:is it really necessary? I might do some OC. If so please tell me a nice one.
If something's not fine with my build please tell me.
Motherboard: If you insist on Asus, don't rule out the Sabertooth P67 or Maximus V.
RAM: Both G.Skill and Corsair are excellent choices, but you're likely to get a better success rate out of G.Skill than Corsair, depending on which type of Corsair memory you use (don't use XMS series, go for Vengeance)
GPU; Gigabyte's pretty decent, but I'd recommend EVGA over all NVIDIA vendors, and if you're going the ATI/AMD route I'd recommend Sapphire and XFX over everything else.
PSU: This is honestly one area where you don't want to skimp. Antec and Corsair both make excellent products. Also check out Silverstone for some higher-end PSUs.
Case: It depends on your personal preference but check out some of these:
The thing I'd advise though with going through a local dealer is that they could possibly stiff you on getting the parts you really want, like going to a bad car repair shop, but the key is to insist on getting what you want, rather than what they tell you what you should want.