When I went to Hawaii, I took a 15, 28, and 50 on an M8 and 20 and 45 on the GF1. This is a 28mm shot. This is a 15mm shot.
It's on an M8, though, which means it's more like 37mm and 20mm. I've noticed that ~40mm is my "natural" length, but I've already got 40mm covered on the GF1. Arguably, I also have 90mm covered.
Essentially, if you want that 15mm shot, you'd better have the 15mm with you because nothing else will give you that shot. You can crop a 90mm shot to a 135mm one.
I probably won't enlarge over 16x20 (if that), and I've noticed that my iPhone enlarges better than I thought at 9x12. I have a good scanner, and my workflow's mostly digital.
Usually the 28 lives on my M8.
Given that 15 on the CL is wider than 15 on the M8, I was considering leaving that lens on there most of the time. It's specialty, but it's neat specialty.
If I took the GF1's two lenses, and 15, 28, 50, and 90, I'd have the following effective focal lengths covered with different combinations:
15, 20, 28, 30, 37, 45, 50, 56, 67, 90 (twice), 100, 120, and 180.
Changing the 90 to the 135 offers:
15, 20, 28, 30, 37, 45, 50, 56, 67, 90, 100, 135, 180, and 270.
The 90mm is a much smaller lens than the 135, though, so I wonder about whether it's really worth that. I'd considered renting a 100-300mm zoom for the GF1. Sometimes you just want to see stuff really far away.
We will have a balcony cabin, but there's no real point in tripod shots due to waves and vibration; at night we'll be on the boat, and on tours, only a monopod (at most) is generally permitted.