Eating in Luanda can be an incredibly expensive experience as the cost of getting ingredients to the country means that prices are high.

There are many good restaraunts in the city, including

Venezia - cracking steaks, served raw with a hot stone so you cook it yourself. Waiters speak English and the restaraunt is air conditioned and very pleasant.
average cost for 2 courses with wine about $100ea

Caix au Quatro - Fabulous location on the Ilha, overlooking the city, in the evenings you could almost be in the western world
food here is very good, but the service is poor if the owners aren't present.
average cost for 2 courses with some wine about $75ea

Fortaleza - A tiny restaraunt with a 30+ year history, located inside a private house.
very intimate and attentive service. Prices aren't too bad either, about $50 for a steak dinner.
Menus are in Portuguese though and not much English is spoken.