Though I am a big fan of the new "big sensor in a small body" trend, it might be nice to see one other sort of low light comparison:
wide open at equal shutter speed on both the G11 and GF-1+14-45.
That would let the G11 take advantage of its brighter [lower minimum f-stop] zoom, by getting the speed needed at a lower ISO speed, and it would bring into play one factor in favor of smaller formats: when lenses are limited by size, weight and cost, the shorter focal length lenses of a smaller format can often be brighter and so allow the use of lower ISO speeds.
Of course with the 20/1.7 wide open, the GF-1 should knock the stuffing out of any small sensor compact in low light!
[Added: ] P. S. Thanks for one thing: correctly saying that the G11 and such have smaller apertures than for example the GF-1 with 14-45 f/3.5-5.6, even though the G11 lens has a lower minimum aperture ratio, sometimes mistaken as being "faster".
For low light speed, there is no substitute for mm! (of aperture diameter)