In reply to George Fisher:
The XF 18-55 is an excellent lens, in terms of image quality, but after a year of use I ended up selling it and getting a small set of primes instead. I've never really liked zoom lenses and I found the unmarked, free-rotating aperture ring on the 18-55 difficult to use (although it's still better than controlling aperture from the camera body, which I believe you have to do with the 16-50).
That's all personal preference really, though. As a general-purpose zoom lens it's very highly regarded and I think you'd struggle to do better.
Here's my lens setup:
1. XF 35mm f/2. Just about the perfect general-use lens for me. Excellent IQ, great autofocus and weather-resistant. I use this most of the time.
2. XF 18mm f/2. My general wide-angle prime. It's a better lens than a lot of the reviews would have you believe, and available for peanuts on the second-hand market.
3. Samyang 12mm f/2. My astrophotography lens. Superb for starscapes and aurora-hunting.
4. A random 200mm Pentax f/3.5 prime with a PK-X adapter. Too heavy for mountain trips but I occasionally use this for wildlife photography.
Edit: forgot to mention the camera bodies I use. I used an X-E1 exclusively for about two years but now have an X-T1 as well, which is gradually taking over for my backpacking and mountaineering trips. It's better in most respects (and, crucially, weather sealed) but the X-E1 is still highly capable, and the image quality is the same from both cameras.
Post edited at 11:38