If you don't have a space limit then actually AMD FX 8320/8350 would probably be your best bet for cheap.
You'll want more RAM than anything (16GB/32GB), and RAID 0 or RAID 10 if the stuff is sensitive. Of course, if this is just a lab then you probably won't care much.

Single gigabit Realtek onboard NIC on a $70 motherboard even would suffice, add RAID card of your choice, LSI etc.