I have an APS-C and currently just have a 35mm prime and a 18-55mm kit lens. I'm considering a 50mm prime but at the same time I wonder if the 35mm is good enough for that since it's a 50mm equivalent anyway. What lenses should I be looking at getting? The kit lens is decent but isn't very sharp and has a fair amount of distortion.

I was also looking at a 55-200mm zoom lens but I also wonder again about distortion and if I really need it.