I'm using an Odroid HC4 as my home server. It has an ARM CPU and it's idling at 3.59 W now with a 1 TB SATA 3 SSD and some web apps that are basically doing nothing, because I'm their only user. It's got a 1 GB network card, like my laptop. I can watch movies and listen to music from its disk on my phone and tablet.

There is no need to have something faster. The SATA 3 bus would saturate a 2.5 GB card anyway. The home network in Cat 6A so it could go up to 10 GB. We'll see what happens some years from now.