I don't know which psu should I choose for my new pc. Here is my pc:

GFX: PCIex EVGA GF 8800 GTS 640 MB
HDD: WD400 GB, 16 MB, SATA II - WD4000AAKS
CPU: INTEL CORE 2 QUAD Q6600 2.40 GHz
Motherboard: ASROCK 4CORE1333-ViiV
RAM: GEIL DDR2 2048 MB / 800

I will not overclock so i don't need expensive 1000W psu. I'm looking at CHIEFTEC GPS-550AB-A - 550 W http://arest.pl/index.php?inc=cennik&katid=14
is it good choice? i'm looking for rather cheap psu which would give my pc enough power.

Any decent 500-550 watt PSU would do you sufficiently for that system, as well as most all potential upgrades.

However, just to let you know, you get what you pay for, and if you get a CHEAP PSU, then you get cheap performance. Are you truly willing to risk that brand new system you have just because you want a cheap PSU? I know that I would prefer not to have to spend another 1000-1500 dollars just because I wanted to save a few bucks...

Take a look here for further recommendations, as well as some insight to other PSU's...

Recommendations by Perkam

Recommendations by Jonnyguru

These are two of the MOST knowledgeable people who know about PSU's, and I would take their advice if I were you.

Look at the lists above and plan on spending at least $40. I've had cheap power supplies fail in just days. A good unit weighs at least 3.5-5 lbs.

Get one of these, you'll be glad you did.
The price has dropped from what I paid for mine, cool.
I'm gona get another one.

http://www.pcpower.com/products/vi [...] how=S61EPS