Well currently I just did a recent build and for well under $1000 you can get the new sandy bridge processor either the i5 2500k or i7 2600k. As far as motherboards that is kinda a personal thing on what you need or dont need. I went with a i5 sandy and a MSI motherboard http://www.newegg.com/Product/Product.aspx?Item=N82E16813130574
with G.skill ripjaw 1600 8 gb this combo alone cost me around $550. This is the best cpu on the market besides going to the i7 sandy but unless you need the extra threads then I would stick with the i5 2500k especially for gaming.