Buying GH2 but which lens

After some good advise on here I am buying the GH2, however I am unsure about which lens?

I mainly shoot landscapes and street photography.

I think the 20mm f1.7 is a must, however I am unsure about which is best. 14-140 or the 14-42 and 42-200 I think it is?

I think I would mainly use the 20mm for general and landscape or would be better with the 20mm and 14-140? I want to keep the weight down but image quality is vital.

Appreciate your help

Ian