I have the e=pl1 with panny 20 myself, and its a great low light combo. I will admit though that somestimes I wish the body itself wasnt quite so bulky. I often stick the body in one pocket and lens in the other when I'm leaving the house, but even with the pancake on its cumbersome in jacket pockets.
The smaller body of the gf2 is tempting to me. I don't think IS is a big deal for social situations, usually subject movement is the issue, not camera shake. In addition, I sometimes find the 40mm equivalent a little restrictive in small rooms or crowded bars/resturants where backing up is difficult, so the 14mm 2.5 would be nice.
I think my next move my be to sell my e-pl1, keep the 20 1.7, and buy a gf2 with 14 2.5. then, ill hold my breath for the rumored oly 50 2.0 and have a nice small prime kit: gf2, 14, 20, 50. I think this would be a really small, enjoyable kit which would be well suited for the type of shooting youre talking about!