I would say get a MSI k8n Neo4-F and replace the chipset block and fan with a zalmen chipset block ( http://www.zalmanusa.com/usa/product/view.asp?idx=71&code= ) That msi board has sweet features and overclocks great. The onboard sound could leave a bit to be desired but I have an Audigy 2 ZS so i dont mind. Cant beat the price on it tho!
i know you said you did not want sli,but how about one of these boards,passive cooled chipset,personally i would,nt trust a zalmen chipset cooler on an n4 board because the chipset runs so hot. link http://www.microdirect.co.uk/ProductInfo.aspx?ProductID=9887