Malawi is my favorite. Current favorite fish is Red Empress. I got some fry, and after about a year, the males are colored up. I even have a female holding now. A lot of fun watching them change.
That's a hard one...I have fish from all 3 lakes that I REALLY like. I would Probably pick Victoria though because if you really look at these fish, they have some of the most beautiful color patterns of any fish I've ever seen. Absolutely stunning.