In the Panasonic lens forum, i asked the same question and got good responses.
The thread is call "one zoom or two zoom kit" i think.
I went for the 14-140 and i'm happy with my choice.
I like the range, the iq, no swapping between lens, fits well in my hands.
It feel like i'm having a dslr again but i use it mostly for video and kids stuff.
I'd say that i use the 20mm 1.7 80% of the time.
Last friday i spent the afternoon skating with my son and his classmates.
I took the 14-140 and took near a hundred photos.
Coming from a Nikon dslr with good autofocus performance, i was surprise
by the ratio of good pictures.
Most of the pictures were on focus. Only 5 or 6 were misses.
I was afraid that for actions pictures the Gf1 would not give me satisfaction but i was wrong.
The Gf1 prove to be a very good choice for my kind of shooting: kids,street,portrait.
I’ll start by saying that I spent several hours on Saturday walking around with the 14-140 on my GF1, and not only did it handle like a charm, but I was exceedingly pleased with images taken at a real mix of focal lengths. Pretty much all wide open, which isn’t al that wide with this lens... This is a good match. Really my first time just walking around with it.
The current rumor is that the GH2 will be available with a 12-70/f2.5-3.3 lens.
OKAY - IT’S A RUMOR.
But with Panasonic set to make announcements soon, it’s very tempting to at least wait. Besides the extra 1 ⅓ stop, you’d get those extra 2mm that I’ve been wanting. And along with the 100-300 lens, and the small 20mm, quite a set. And if the lens design keeps up Panasonics current high standards, that’s going to be quite a lens. The 14-140 is a good bit sharper than the EF24-105L that I used (before selling) on my 5D.