Hi all!
I am trying to build inexpensive office PC. It will be used mostly for Autocad (only 2D, NO 3D) and standard office works (MS Office, emails, web browsing etc). I have limited budget (~1200USD inc. 2x 24" monitors).

Intel Core i5-3570 (lets keep it - best power/proce ratio i think)
ASUS P8Z77-M PRO Z77 mATX (maybe standard ATX will be cheaper?)
Scythe Samurai ZZ SCSMZ-2000. (any other recomendations in similar price range?)
Kingston HyperX 2x8GB DDR3-1600 Dual Chanel Kit Non-ECC CL10 Red (16GB is what my boss wants - and i am ok with it)
ASUS GTX550Ti 1024MB 192bit PCI-E DirectCU. (basically taken to have 2 digital monitor outputs and Direct CU for quiet operation)
WD Red WD10EFRX 1TB sATA III 64MB. (lest keep this one here - storage drive)
Intel330 SSD 60GB SATA3 (for OS and apps)
Silverstone TemJin SST-TJ08B-E USB 3.0 Black (not too cheap, maybe changing it to normal ATX will lower costs?)
Antec EarthWatts Green EA-500 500W 80Plus Bronze. (Seasonic X series are so hard to get in Poland...)
ASUS DVD Recorder DRW-24B5ST/BLK/B/AS Sata Black Oem.
Iiyama ProLite PLE2473HDS-B1 24" LED x2 (TWO is a must)
MS Windows 7 Professional OEM SP1 64-bit

Any recomendations?
I want to achieve enough power for work (basicaly CPU threads, RAM and drive speed matters for autocad in 2D) and rig must be quiet (lets say inaudible from 1m in office with background office noise - radio, talking etc).

I'm not sure about the GTX550Ti. The new 600 series are substantially better for energy efficiency but I would also not rule out modern onboard graphics which can adequately run a spanning desktop across 2 monitors.

If you're looking to save a little money on case and are going for an Antec PSU anyway (you don't need 550W) then what about going for the Antec NSK3480? This is similar sized to the TJ-08E, very quiet and the PSU is a 380W Earthwatts which will be sufficient until you can source an X-400, a PSU that fits in it very well!

-60 GB SSD for OS and Apps is not enough. Naked Win7x64 is around 30-40GB.
-you won't need a Z77 board, you could switch to a less expensive chipset. Using mATX board will also save some bucks
-550TI could be replaced by a 640/650 model, because older GPUs do not enter power saving mode used with multi monitors
-Temjin is a little bit too expensive, i'd look for a cheaper case (Bitfenix or cheaper Antecs)

$1200 including the two monitors that sell for $400 each or excluding the two monitors?

The ASUS P8Z77-M (non-pro) should do fine. It can drive two displays at 1920x1200 resolution, so no need for a graphic card, unless you need it for Autocad.
Are you sure 60 GB SSD is enough for Os and apps?
I would recommed 2.5" 1TB storage drive for noise, but in an office environment you might not notice the difference.
Spend a few € (Zloty?) on a bigger CPU cooler, the Mugen 3 or Ninja 3 are good, the Thermalright HR-02 Macho is a little bit better.
Antec New Solution NSK3480 costs about the same as TJ-08 E and comes with an Atec PSU. It is big enough for all CPU coolers I recomeended (as is the TJ-08 E).

The OP's desired WD Red 1TB is extremely quiet. Current SPCR reviewed champ, in fact. I doubt any notebook drive is actually quieter.

I would also suggest to the OP that onboard video for the 2 monitors is definitely worth trying, save a bundle of $ and power/heat. Onboard video is not a dirty word any more.

The question is - will i be able to connect 2 monitors to integrated gpu using 2 digital inputs? (dont want to use dsub vga port...)

Thanks for all the tips, especially for pointing Antrc case w/ psu!

Sure. Ivy Bridge can handle those two 1080p monitors with DVI-D and HDMI. So, connect one monitor to the HDMI out and the other to the DVI out.

If need be you can get an HDMI-DVI adaptor if your monitor of choice does not have an HDMI in. Similarly display port-DVI adaptors are available if display port is available instead.

I'll risk sounding like a broken record again, but I can vouch for the prowess of the Intel HD 4000 inside the i5-3570K in single monitor use for resolutions up to 1920x1200. I don't know how well it will handle dual monitors, but it is surprisingly good, even compared to budget graphics cards and not just old Intel integrated graphics chips. It is definitely worth giving it a go, as Mike said - my workspace has never been cooler and quieter than with the HD 4000!

If you do go for an alternative in graphics, I think the best bet would be a GTX 650 Ti, which is currently the most bang per watt AND the least power hungry "mainstream" GPU. Less power, less heat, less noise. The cards regularly come with 2xDVI-out as well, and an Nvidia GPU would support CUDA, in case that ever gets supported in your work software. You can forget about the GTX 5xx cards, they've been outperformed in every way.

The SSD looks to be really small. Samsung 830s have amazing deals from time to time, and an older, established performance drive like the Crucial m4 (it is no slouch even today I tell you what) you might be able to find for cheap. The (small) price bump up to a 128 GB drive is seriously worth it in terms of performance and avoiding space issues. This would be the wrong place to save.

I second Pappnaas' observation about Z77 being unnecessary. If you won't be overclocking or using multiple GPUs, H77 boards have been much more affordable. See this Puget Systems blog post for further reference: http://www.pugetsystems.com/blog/2012/04/12/z68-z77-and-h77-whats-the-difference/. Only if the Z77 board has OTHER necessary features or matches H77 pricing should you consider one.

If the case+PSU doesn't pan out, check out Nexus 430 W Value for PSU - extremely compact, SPCR Editor's Choice and as the name suggests, will certainly not break the bank.