Hi again !
I wasn't using my Pentaxes for some time and this weekend I made several tests with them and I gave up on the DA18-55 WR.
This kit zoom lens is better at F7.5 to F8 and the image quality at this aperture is quite nice but the borders are horrible wide open.
All the other lenses I have for it are primes like I said before and I don't like the idea of changing lenses every time, especially when travelling with family, I'm sure you all understand
After taking a careful look at the options people suggested here, I think I'll go for the Pentax 16-85 or the SIgma 17-70 "C". Both are very capable lenses, I'll see what I can find in Paris during this trip.
What I like about the Pentax is the IQ and WR
About the Sigma, if focus much closer and has a larger aperture, making it more versatile. And it's also less expensive.
Just one more question, This 16-85 has a buil-in DC motor for what I saw. Is it reliable ? I heard lots of complains about the Pentax ultrasonic motor and I never had a Pentax lens with a built-in motor.