You should probably know that a Z97 motherboard and an i5-6400 aren't compatible. You should also determine what case size/motherboard form factor you want as it will have a bearing on other things. You may also want to consider the efficiency rating and modularity you desire of the power supply you choose. You probably want to think about what the PC will be used for so that the parts choices and can tailored to those uses and potentially save you money or get you more computer for the same money.