Nonsense. My file server has a LGA1155 Ivy Bridge G1620 in a H67 mini-ITX board, 2x4GB of RAM, 1x SSD, 1x 500GB 2.5" scratch drive, 4x 4TB 3.5" Seagates, and running Windows 8.1 (I use Storage Spaces), and it idles a smidge over 20W at the wall (this is when the HDDs--the biggest power draw--have idled long enough to spin down). Its maximum draw during a power stress test--that is, I started to copy data from the 500GB drive to the 4x4 array to get all 5 spinning drives active while also running an AIDA64 stress test on the CPU, RAM, and GPU--was just a bit north of 60W.
My HTPC, which also has a dual-core LGA1155 Ivy Bridge, idles around 15W and has a maximum power draw of somewhere between 20 and 30W (it's been a while, so I don't recall the exact numbers). I'm sure you can do even better with Haswell, and certainly with Bay Trail.
Yea, it's not quite as low as my store-bought router (which comes under 10W; and BTW, I personally recommend a good high-end store-bought loaded with DD-WRT instead of building your own), but at least it's not off by a whole order of magnitude like it would be if using old Hotburst-era technology.
The days of 100+W computers is history (unless you're talking about a gaming rig, but that's an entirely different beast).