Thanks duders that was useful. Seems like the Xbox is much better when it comes to consumption while it's running - but the saving during standby mode makes up for it a bit. Must be that Kinect waiting for you to say "Xbox ON". I hope the Xbox doesn't use too much power while you're watching TV through it.
Going from this I think I'll leave my PS4 on standby a couple nights a week and just turn it off the rest of the time. That way it can still get updates and stuff like that.