So I re-arranged things in my basement and have powered off the Dell P/E 1950. Network services either have been, or will be, moved to the SunFire X2200M2. The Dell will either go to the colo or will be sold, have not decided.
But more to the point: with the Dell gone, my Kill-A-Watt is showing 145 Watts being drawn, down from 480. (Interesting: when the power supplies were plugged in but the computer wasn't running, it was still drawing 30W -- presumably to run the iDRAC or baseboard manager thing.)
Which means! The 1950 running draws 350W. Which gives you a per-day cost (at $0.10/kWh) of $0.84, or $25.20 per month for 51 kWh of electricity.
(I have gone back and forth on using the Sunfire instead of a SRX210 that I have kicking around. The fact of the matter is that I like having a device that can record netflows, network usage, and other statistics.)