For a cost/performance trade-off, I would consider:
http://www.newegg.com/Product/Product.aspx?Item=N82E168191039618 cores for $159
For an inexpensive board:
http://www.newegg.com/Product/Product.aspx?Item=N82E168131285216G SATA, 1G NIC, USB3, 32G max memory, $90
6 cores for $120.
My last 3 dev boxes have been AMD, and the last ~10 Virtualization hosts have been AMD. Unless you are a gamer who makes his rent on twitch latency, AMD is the better business choice.
For some benchmark data about processors:
http://www.cpubenchmark.net/high_end_cpus.html
