What are the recommended specs for intel core i7 2600k?

I recommend you get the cheapest ATX motherboard you can get from ASUS, MSI, EVGA, or Gigabyte. And you will not need anything near a 750w power supply. Try saving some money and get a 550w power supply (preferably Corsair, OCZ, Thermaltake), then use the money saved to get a better video card. I don't know why you want to overclock your CPU with a horrible bottleneck from your GPU. You can get by with a cheap Coolermaster 212 CPU cooler and easily overclock a i7 2600k to around 4.5ghz without high temperatures. Get whatever case you prefer; a cooler master HAF 932 is a common choice, I also recommend a NZXT Phantom for the same price.