Hey, building a new pc

You plan to OC? Xfire? If you dont plan to Xfire, then 850W is overkill for the PSU  
If you are gonna OC 650W should do fine. Everything, other than that, looks great!

850 is for futureproofing + cpu OC.

But other than that, all the parts fit well and wont have any problems building the pc ?

Im not good with stuff in the case itself, but I can say that everything is compatible  
Oh, PC hardware will most likely use less power in the future so yeah. 700W/750W is good enough if you really want it futureproof   Your only gonna use 800W when you have a MONSTER PC (multiple CPUs, GPUs and the like)

well if you want the 850W then that's your choice it really is not needed you can run two 7870 and OC on a good 750W no problem but your build looks good and yes all is compatible   You need a aftermarket cooler if you plan to OC your CPU i recommend the COOLER MASTER Hyper 212 EVO

yep, gonna get that cooler aswell and swap in for a 750W psu

In that case you also need low profile ram so it doesn't conflict with heat sink look for any of these where ever you buying from RAM:G.SKILL Sniper 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBSR
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM:CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CML8GX3M2A1600C9B
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM:CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Low Profile Desktop Memory Model CML8GX3M2A1600C9
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM:Mushkin Enhanced Blackline 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model 996995
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

ram:G.SKILL Ares Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-1600C9D-8GAB http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM:Crucial Ballistix sport 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model BLS2KIT4G3D1609DS1S00
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

i have corsair vengeance (the bigass heatsink ones) and a hyper 212 evo aswell  
i have them on the most furthest slots from the cpu (ddr3_1 and ddr3_2 dual channel)

 

Oh o.k. well then your good to go all is compatible and very nice build bud  

also, is this fan good for intake and outtake ?
http://arvutikeskus.ee/est/TOOTEKATALOOG/ARVUTIKOMPONEN...

It has 68CFM at 21db.. thats pretty quiet and decent ? yes ? no ?

I use a Gentle Typhoon AP-12 on my case as a front intake fan. Very quiet, and pulls air through the front filter.the one you linked to looks alright i have never used those before though.

yea im planning to install these dust filters on each fan aswell:
http://arvutikeskus.ee/est/TOOTEKATALOOG/ARVUTIKOMPONEN...

so how much cfm/rpm i need from a fan to decently pull air through it ?

Filters just reduce airflow. If you are planning on maintaining a PC, dust clean out should be part of your normal routine. If you forget to clean dust filters, they clog and become far more detrimental to cooling than not having them at all. These work well and are cheap http://www.newegg.com/Product/Product.aspx?Item=N82E168... (They also come with red or blue LEDs):

yeah, but if fans keep pulling dust into the case then a lot of dust accumulates in the hyper 212 radiator and elsewhere and then it settles down and cant be blown away with air compressor but has to be wiped away... i hate that

Very true i clean my case more than most so i wasn't really thinking about that i clean my case once a week so dust filters are not needed for me