If you live near a Micro Center they sell Core 2 Quad Q9550s for $169.99 I believe (if they still stock it) pickup only, which would make a good upgrade. Otherwise I suppose there's not much point pumping too much $ into a dead platform, and you'd be better off with a Core i5 750 system, unless you don't mind waiting for SB.
Seeing as SATA and or USB 3.0 & CrossFireX/SLi aren't necessary, a good board would be the MSI P55-CD53 for $109.99:http://www.newegg.com/Product/Product.aspx?Item=N82E16813130240
USB 3.0 is quite handy in the future, and this is a cheap board that comes with it:http://www.newegg.com/Product/Product.aspx?Item=N82E16813157203
CrossFireX is available on that board, but won't work well... but you don't mind so yeah.