Get a group and go have fun.
Abay may be my favorite place in the city when I have a group of friends ready for food.
Sitting at the big round table and sharing the different dishes, drinking wine, and sharing stories is a must.
Choices I'd recommend:
Pumpkin soup - Creamy, refreshing, and delicious.
Zilzil Tibs - Great spice and probably the best compliment to the injera bread.
Doro Wat - chicken with lemon is quite nice and a good switch from the spicy and hearty zilzil.
Shiro Wat - Creamy lentils, peas, and chickpeas in a spicy sauce. Good stuff.
I've tried many of the dishes, but these 3 are musts.