The 18-200 is a great "set it and forget it lens" as you put it.
I have the original version, and even though I tend to shoot with primes when I can, I still find myself stuffing the 18-200 into my bag for the versatility it affords.
It is particularly useful when needing to accomodate a variety of subjects/focal lengths while operating in an environment that isn't particularly conducive to swapping lenses (dusty, crowded, etc).
I started my e-mount lens collection with my NEX-5, so I have quite a few. But if I was starting today, my kit would probably start with the 35 f1.8, the 18-200, the 10-18 and maybe the 50 f1.8. And I suspect that would have done pretty well for me for some time.