So I have the exact same issue as the OP. The intel usb 3.0 eXtensible host controller will wake up my HTPC (ASUS H87i-plus, i7-4770k) 15 seconds after it goes to sleep. i am interested in the helpful answer that jdkrause provides, but I am a novice at windows 8 and cont figure out how to turn off hybrid sleep.
Does anyone know in 8.1 how to accomplish this?