Hi. What is the rest of your system specs? What is your CPU and motherboard budget? Do you know which processor you're looking to get? If this build is for gaming and you want to be able to overclock the processor, then get the i5-3570K and the ASRock Z77 Extreme4 or any Z77 board that you prefer. If you're not looking to overclock, you can just get the i5-3470 or another i5 and a H77 motherboard.
You should have a plan of what components to buy before you start buying them. Since you prefer Intel, we'll go with that. What's your budget for the CPU and motherboard? Do you plan to overclock the processor?
yes, I plan to overclock and I was planing to buy the i5-3570K, what you suggested. but the problem is with the Motherboard. there are so many options. I would probably want the mother board to have atleast 2xPCI-e 3.0 so in the future I would be able to add an additional GPU as well
Extreme 6 contains few expansion slots more,uses different MOSFET heatsinks,has a display port and some other minor differences.Also extreme6 is bigger in size than extreme4.I would pick extreme6 only if I need higher clocks when overclokcing and to run it for a longer duration.The heatsinks on extreme4 are reported to get heated more.