Here is an enclosure kit that turns your Raspberry Pi into a mini desktop computer. Element14’s Pi Desktop Enclosure Kit gives you an on/off power switch and RTC. It has an mSATA SSD socket and controller, so you can create your own media center.
The kit comes with a heat sink, USB adapter, screws, and everything you need to get started. The enclosure is compatible with Raspberry Pi / 3 at this time.