For bluray I'd recommend a ps3, increases the options for games as well.
If you can afford it, I'd definitely recommend a Core i7, a critical component like a CPU is always the hardest to upgrade after the fact. Even if it takes a few more weeks to save up the cash, I think it's worth the wait

I'm with Aliasalpha on this one, you won't regret the i7.
I just put together a computer with an i7-875K and it is amazing! If you're planning on doing any overclocking, you'll want it for the unlocked multiplier. Of course, because it's made with overclocking in mind, it doesn't come with a heat sink.
That'll make it about $150 more, but it's totally worth it.
It also uses the 1156 socket, so you won't have to find a different motherboard.

As Hamper noted, his board does not support triple channel. Dual channel only, so it's either 2, 4, or 8 GB of RAM.
As for a Blu-ray drive, something to keep in mind is Windows 7 does not natively support Blu-ray playback, due to licensing issues If Detlik wants to play Blu-rays on his machine, he'll have to get the proper codecs elsewhere.
Detlik: my current rig is housed in a HAF 932. It's a very nice case to work with, due to lots of room. Some people don't like the look of it, but I don't mind it and the room it provides is the clincher for me. Besides, I got a good deal on mine, so it was an easy decision.
I would also suggest a Corsair PSU. I've got the HX850 in my rig and it's rock solid. If you want to read some reviews before deciding what to get, I'd suggest heading to jonnyguru's site and checking out some of the reviews there.
Keyboard and mouse: I'm partial to the Logitech MX580 mouse. Love this thing and it works great. For a keyboard I'm using the Logitech G11. Been a great keyboard for me, although it did suffer from intermittent power loss for a short stretch (it would lose power for a few seconds every couple days, then power back on), but that sorted itself out (never did find out what caused it).
Not sure I see the need for a 1 TB HDD for your OS unless you're thinking you might short-stroke it. Perhaps an SSD would be something to consider (as mentioned before) if you have can afford it.
RAM: I've used Mushkin in some of my other builds, which has been great RAM, but I went with GSkill in this latest build (triple channel though). It's been excellent as well.
Anyway, hope that doesn't muddle things up even more for you.

4gb is perfectly fine nowadays and you can easily add four more in a year time.
there is no real benefit from triple channel in comparison to dual channel when it comes to gaming.
so yeah
great system.

Choose a silver moniter.

And otherwise is it a good motherboard? Or could you recommend me some with triple channel that would be equally good? And which i7 would you recommend?
I am thinking about buying Intel i7 930 but it is in different socket (1366) so what is good motherboard for it?
Is this one good Gigabyte GA-X58A-UD3R - Intel X58?

GA-X58A-UD3R + i7 930 are my most recent upgrades and I don't regret them one bit.
The board is a relatively cheap one, because with mobos the performance differences are virtually nonexistent. What mattered to me were the 2 USB 3.0 ports for future-proofing, SATA 3 support (for the same reason), external "CLR CMOS" button to avoid screwdriver+pin or battery-for-30-minutes tricks every time you mess the BIOS up.
Tripple channel means you can either go with 3GB or 6GB of DDR3. If going for the former, what's the point in buying a 64-bit system ?
As for Kave - I've come across this little thread yesterday, while wondering if the incredibly overpriced Psyko 5.1 might be better than what I have... Turns out - not really, so I can rest easy :].
Oh, BTW - the Kave has vibration on lower frequencies, although I had to figure out how to enable it on my X-Fi... I think it's awesome, but there are people who don't enjoy it quite as much.
Also - what are your thoughts on S3D ?

So the new mobo supports triple channel? Also I must confess that I dont know much about S3D (Beginner in building systems)
Which PSU would be better OCZ StealthXStr​eam 700W , OCZ StealthXStr​eam 2 700W or Corsair HX750 750W? And how can I see how many W would my system need?

Check the above. I went a little overboard and bought a 1kW PSU, just to be on the safe side ;P.
Also - from what I've read - look for non-modular (no detachable cables) PSUs if possible. They might be less convenient, but they're allegedly better because of less connections between the power source and the component.
As for S3D - have you seen Avatar ;) ? That's what got me convinced, since I figured that the only thing better than passing Max Payne 2 for the nth time would be to do it in goddamn 3D :D.
Still - getting a 120Hz monitor won't hurt even if the whole 3D is merely a passing fad. You can still use the additional 60Hz in 2D mode, which makes sense if you want to go for a powerful GPU. Also - standard GPUs nowadays are insanely powerful, so people either go for multi-monitor setups (IIRC - with ATI cards you can use 3 monitors with 1 card) or 3D (which uses 2 DVI ports for a single monitor).
The monitor you picked is "average", cross check the prices of either this or Alienware AW2310 (which is more expensive yet hardly worth it, as far as I've read) if you wish to go with 3D (and, of course, add a GeForce 480 to the mix ;P).
If you go with socket 1366 - sure.

This is the build I got
http://www.gog.com/en/forum/general/awesome_new_gaming_pc_on_the_way/_/1
extremely good machine.
The GA-X58A-UD3R Mobo is indeed a triple channel and bloody ambitious, the overclock options let you try and clock a 3.2Ghz CPU to somewhere over 28Ghz. Naturally I've never tried it because I prefer my system to NOT be on fire but the option is nice

3? with ATI you can run 6! the only limitation is they have to be display port monitors.
The 480 is over priced btw a 460 is around the price of a radeon 5830 and has most of the power of a 480 in the real world (it's slower in heavy tesssalation environments but no games use them)

Some games use tesselation and its a major selling point of DX11, I'd heavily recommend focussing on that as a selling point in a card since it's likely to be the thing that makes your card obsolescent first in the same way dynamic lights were this time last decade

The only case where a difference was noticed by most reviewers was the extreme tessalation option in Heaven which even the implementers admit is stupidly over tessalated (2-2000 triangles per pixel) seriously theres a pic out there that shows the extreme mode in wireframe the whole screen is white with no gaps

I've seen enough tesselation examples to convince me it'll be the next big thing. Basically it allows developers to be a bit lazy and let the GPU do more work. It's not going to be an effect that you notice if they get it right but you'll notice the lack when walls or pathways are flat and simple rather than realistically bumpy

Holy crap, I stand corrected ! Still - I find the bezels unbearable and would prefer a single HUGE monitor to many big ones ;P.
While I'm admittedly a nVidia fan... look at this :\.