My vote would be for Prague. I've never been, but am going this Christmas. Been to KL...the airport is awesome, but the city seems strange to me. I can't put my finger on it...maybe it's the Muslim presence and I'm just not used to that. Taipei...only stopped at the airport and it was like jumping back in time. Very militant, old and musty. But flying out over the island it looked beautiful! Never been to Jo-burg, but my intuition (and others advice) would tell me it's not the city I'd want to spend much time in.