Few weeks ago I wrote a list of very fast 50mm lenses. But if you are looking for fast lenses you should also take a look on the very good Konica Hexanon 57 f/1.2 lens
If you want to see some image samples click here:
dpreview forum (on the GH1)
e-p1.net (on the E-P2)
flickr.com (on the GF1)
UPDATE: Lumix L1 + Konica samples http://iztokx.blogspot.com/
The lens itself sells for $550 on Ebay (used)
If you have some image samples send me your links at 43rumors@gmail.com
And also send me your test with other fast lenses!
Thanks