When I was in Joburg, about 7 years ago, we stayed in the Melville neighborhood. We only stayed 3 days before headed to Botswana, but I loved the area. There were tons of funky shops and fantastic restaurants on 7th Street. We stayed at the Melville Manor Guesthouse. It was very nice, but not super fancy.
Thanks Melville was one of the three suburbs I heard was good to locate yourself as a tourist (I'm thinking similar to Newtown in Sydney, but that analogy probably doesn't work well on this board!).
Blessed unfortunately we couldn't fit Cape Town in this trip, it was high on my list but we just couldn't squeeze it in, from what I hear it's a beautiful city.