I'd suggest Intel Core 2 Duo E8400
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115037
or eventually Intel Core2 Duo E7500
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115056&Tpk=e7500
If you want something <$140, then go for the Wolfdales, but if you want something $140<, then definitely go Quad. If you had an LGA 1156 motherbaord, then you may want to go clarkdale, but in this situation, definitely get the Core2 Quads.wolfdale all the way if your motherboard supports it.