I am still quite happy with my old Sun Fire X2270 M2 with Dual Xeon X5675. Not new, but its 12 physical cores, 88 GB RAM and 4 hotswap SATA drive bays in a 1U rack unit make it quite a decent machine for running a couple of VMs.
I also like my Dell T320 Rackable Tower server. It has room for 8 hotswap 3.5" SAS drives (or 16 2.5"), redundant power supply, and you should be able to get it for under $300. With a Xeon E5-1428L V2, mine is still quite capable and uses between 140 and 160 W (with 8 disks).