For the significant difference in price (around 200$s at the time of this writing)
, the Olympus E-PL1 is a clear winner over the Panasonic GF1. The E-PL1 has most of the functionality a enthusiastic photographer would need and has one of the best quality photo output among the micro four thirds system cameras. However, if you are a user who need the extra LCD size, shutter speed and more easily configurable controls, then the Panasonic GF1 would be a better choice.