EPL-1 with Summilux 25mm f/1.4 OR the Panasonic GF3XT with a LUMIX G X Vario PZ 14-42mm/F3.5-5.6 Len

The PZ 14-42 has some well documented problems with "shutter shock" on Panasonic bodies. You might get lucky and get a great lens/body pair, but in my experience the PZ 14-42 lens works much better on an Olympus camera - specifically the E-PL1 which you already have. I tend to prefer Panasonic slightly over Olympus, but I have to say, in this case you probably should stick with what you have. I'll bet it works great. Some day in the future you could pick up the Pancake Zoom if you want to add a pocketable, versatile, and pretty decent lens to your kit for times when the light is brighter.

Sterling
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Lens Grit