Asrock Rack c602 mobo
2x Xeon e3-2650Lv2 (20c/40t)
8x8GB Samsung DDR3 ECC
generic EATX case with fans
2x CPU heatsinks
3x case fans
XFX fanless modular PSU
if the price and specs alone aren't compelling enough:
it runs idle at ~50w
it has a similar passmark of >15000
it has 4x GbE ports
it has 4x PCIE3 slots (!)
I'd never heard of iLO, which other commenters mention as a selling point, but a quick search leads me to believe this is HP's take on IPMI, which this mobo has.
originally built as an HTPC server, I had 2 main criteria for my build: cool and quiet. hence opting for low powered processor versions, 0db PSU and PWM case fans. if you don't require these criteria you can knock ~20% off the budget.
there was so much power being unused that I binned a few other devices (namely crappy ISP-provided router and tv box) and made this build the heart of my home network. it is now my family's router, firewall, adBlocker, movie and tv server, game server, free cloud storage manager (synced to every household device), OS updates cache, music streamer, torrent client/server, VM server, web server, database server, VPN client, proxy server, etc., the list is virtually endless. these are all run simultaneously with ample resources leftover for frequent workstation usage.
I should admit that I thoroughly researched every component's specifications and price, and as such it took me around 3 months of waiting to source them.
I also admit this use case and learning curve is not for everyone, but it was ultimately a rewarding experience for both my brain and wallet.
I admit I was more lazy, I have a separate room for this machine so I don't mind the noise that much. I just configured what I wanted and ordered it. I only did some research on the CPU performance.