Good question. It will be interesting to see the variety of answers.
I carry six balls with me and tend to cycle through all of them. The house shots we see at the houses in my area are varied at best, but I like it since it keeps everybody on their toes and not knowing exactly what's coming next.
As for the setup itself I like to keep a heavy oil asymmetric with surface, a medium-heavy oil asymmetric that's usually polished, a light-medium oil symmetric hybrid or solid with surface, a light-medium symmetric polished pearl, a plastic spare ball, and then the fifth ball depends on what I'm getting out of the two symmetrics.