I just bought a bunch of Dell Precision T3610s for our office last year. Zero complaints so far though it did struggle with an imported 1.5GB STL with 32 million facets. I'll give it a pass on that one. I think these were roughly $3600/EA at the time.
Xeon E5-1650 v2 @ 3.5GHz (6 Cores)
NVIDIA...