There is also this attachment for the XB1. It connects to the side of it, but you can put a 2.5 hdd in there while also giving you 3 USB ports in the front. For people that want a cleaner look.
http://www.amazon.com/Collective-2-5-Inch-Enclosure-3-Front-xbox-one/dp/B00T76ZGDO/ref=sr_1_1?ie=UTF8&qid=1426313363&sr=8-1&keywords=collective-minds-xbox-one-media-hub