for a video card you could pick up a recertified 6800gs (130$) or a x800GTO.. for motherboard you could search around newegg.. i'll give it a look right now as well
http://www.newegg.com/Product/Produc...82E16813128306
there's an SLi Gigabyte mobo for like 75.00
http://www.newegg.com/Product/Produc...82E16814130063
recertified 6800 gs 130.00
http://www.newegg.com/Product/Produc...82E16814131007
x800GTO 87.99
those should all do well, but i myself recommend the 6800gs