Mobo: Check out the Gigabyte GA-P55A-UD3. It's newer, has an improved socket (the previous version were prone to failure with overclocking) and has USB 3/SATA III support.
RAM: Over here in the US, Corsair is really expensive. I would check other brands (G.Skill, Mushkin, Kingston) for cheaper prices. Also, you should be looking to get some CAS Latency 7 sticks. The speed (1600 mhz) isn't nearly as important as the CL (also know as the timings).
HDD: Switch that for a Seagate 7200.12 1 TB or Samsung Spinpoint F3 1 TB. They're cheaper, faster, quieter and run cooler.
GPU: I'd want the 5870 personally. It's more powerful, so there's room to grow into it. I would avoid the newer nVidia cards. They're more expensive, only slightly more powerful, run extremely hot and suck up a lot of power.
Case: I didn't see one listed, so I don't know if you need one. If you do, the HAF 922 is an excellent choice. Other good ones are the Antec 900 or 1200, Coolermaster Cosmos (white or black versions), 690, and 690 II.
Yes, actually that's the mobo i was planning to get, just confused it right there on the website.
Well, I haven't come down to a conclusion yet about RAM and I'm still not sure so any further advice and insight on RAMs would be useful. I'm quite a newbie with hardware so I don't know much, I honestly just looked at the mhz.
I haven't found the HDD in some shops i browsed here in greece so I might stick with the caviar black, as far as I know it's decent.
About the GPU, I was wondering whether to wait for new drivers for the gtx470 since I've seen people say that they might boost, but I'm not very trustful about that and don't really pay much attention to nvidia's new cards. I'm pondering whether the extra 100 euros or so are worth for 5870 from 5850.
I'm looking for something cheap as the case concerns me because I want to spend my money on the system.
I'm also doubtful about the PSU. What do you think?
Also, last but not least, I've heard people say that a 5870 cannot reach maximum potential with an i5-750. Is it true? If I'm gonna spend that money, should I buy a more expensive or better cpu like i7 or something?
Don't get Windows 7 32bit. The 64bit version is better as it can utilize more than ~3.5GB of RAM. I've read that security is better as well, and there's no need to be worried about compatibility with older programs.
If you decide to get the 5870 then you will have to be careful about the choice of case, as it is quite a long card. A good budget case that can fit it is the Antec Three Hundred.
750W is not needed for a single card setup. The only reason to get more than a good 550W PSU is if you want to be able to replace your single card with a monstrously power hungry single card or later decide that you are going to build a system that can run two cards. I think I would prefer this one over the Silverstone in your list: OCZ StealthXStream 700W €91 Mostly because I've read reviews of that OCZ one, and they were favourable.
Disregard what you heard about an i5-750 holding a 5870 back, it's tosh. Also the i5-750 is a very good gaming CPU.
Yea, that is a pretty good deal, the next RAM that is anywhere near it in performance is a €210 set. There will be no benefit to getting 6GB of RAM, as 4GB is plenty for gaming. And If you did get 6GB it would have to run in single channel on a Lynnfield motherboard, which would be reduced performance compared to dual channel.
Is it worth it to change I5-750 for I7-860? And if yes, should I change anything on that system, like a mobo or something? I got a few extra money and I decided that if i'm going to buy a pc, it should be worth it.
If you switched to the i7-860, you wouldn't need to change anything else. However, it's not worth it just for gaming. The i7-860 only gives you improved performance for heavily-multithreaded tasks like video/audio editing.
The i7-920/930 would require more significant changes (different mobo, typically 6 GB RAM), and in the USA, results in an additional cost of between $150-200. Again, this isn't worth it for just gaming purposes.
I read that the HT i7-860 has isn't used in games today. Is it possible that it will perform better in 1-2 years? Will games start using HT? I need something future-proof, so that's why i thought of these two.
I don't think we're likely to see games that use more than 4 cores within the next couple of years. Consider that 4 cores have just recently become mainstream, and game developers are typically at least 1-2 years behind hardware, if not more, because they need to design for a wide audience, not just people that have the most recent gear.
Since hyperthreading doubles the available logical cores, making it appear to the computer that there are double the number of cores available, that would give you 8 logical cores, which is definitely not going to be in use by most games for a while yet.
I don't think there's going to be any significant reasons for most gamers to have more than 4 cores for the next few years. As mentioned previously, if you do more than game, it might be worthwhile, but it's simply going to save time, it's not make-or-break by any means.