Gaming PC- Mobo

So I'm in the process of building another PC (around a $600-$650 budget) and I want to see about getting a motherboard that has plenty of slots for a GPU similar to a 650 or 660. I don't know much about how pci slots work and all and am not really sure about which things fill up those slots so if somebody could help that'd be great :D

get this mobo it supports sli and xfire. 

http://www.newegg.com/Product/Product.aspx?Item=N82E16813157293

i would say go for a AMD build take the Asus M5A99FX pro R 2.0 board. with  a FX6300 or a Phenom II  X6

I agree with misteryangel, AMD is on the cheaper side with still great performance and Asus mobo's are quite reliable in my opinion and the M5A99FX mobo has lots of nice features so yeah.