I would look at the Intel Core i5 series CPU and a Gigabyte or ASUS socket 1155 motherboard. Just select the model which best fits your budget. These are compatible with most major memory brands such as Corsair, Kingston, Mushkin, Gskill, etc..
You will need to go into the BIOS as the board first boots up to insure that Virtualization is enabled. It is on by default on most boards, but I have seen some that were not.