I was in Addis twice last year, about average for me for the past decade or so. Usually on a few day layover to/from Mogadishu or elsewhere in Somalia. I like the Ghion Hotel - very central and not the gilded edifice that is the Sheraton*. (The Hilton, one road over is a little more...humble.) I don't often eat in restaurants - beyond my budget for the most part - but my (local) co-workers often have group dinners at Yod Abyssinia; it's pretty welcoming/easy, without being totally touristy.
The National Museum is about the only leisure thing I have had time for, plus several churches and mosques you will see while walking.

* Rumor is that it was "fancy-ed" up for Hilary Clinton during her First Lady days.