Hi hapa, I'm not an expert to suggest you which lens but after reading this report http://craigmod.com/journal/gf1-fieldtest/ I bought GF1 with 20mm kit lens. I'm really happy with it.

For pricing I recommend this seller http://forum.lowyat.net/topic/672153 to get your Lumix gear. Just bought 7-14mm lens from him... the cheapest price in town... no worry he is genuine...

I assume you have limited budget... to start with, you have only 2 choices pencake or 14-45mm lens. 14-45mm is good lens for outdoor pictures. For indoor or night you still needs a good lighting. Built in flash can cover but with some limitation. Same like my situation before... finally I select pencake because of the higher aperture... and user recommendation...
You still can upgrade the lens later once you have enough budget.