I beg to differ from Robbie. Your comments on DOF and lens choices are inaccurate.
In terms of DOF, the difference between 7D and the Gh1 is rather small. In practical settings out in the field, I don’t think it makes much difference.
The larger the sensor / film area, the more shallow DOF. Here are some figures to look at:
Motion Picture 35mm, 1.85:1
20.96mm x 11.33mm (diagonal: 23.83mm)
Super 16mm
12.52mm x 7.41mm (1.69:1 / diagonal: 14.55mm)
APS-C (Canon 7D)
23.7mm x 15.6mm (1.52:1 / diagonal: 28.37mm)
Micro 4/3
The sensor size: 18×13.5 mm (22.5 mm diagonal)
imaging area: 17.3×13.0 mm (21.6 mm diagonal)
m4/3 is 10% smaller than 35mm motion picture, 30% smaller than Canon 7D. It is still much larger than super 16, and much much larger than any video cameras, even 2/3″varicam or F900.
Regarding lens choices, m4/3 is known for being one of the most adaptable camera ever. With its very short flange depth, you can find lens adapters that allows you to use pretty much use any lens made in the last 40 years. Just check ebay for micro 4/3 lens adapters. You will be amazed by the whole new world of possibilities with lens choices.
My own lens package for GH1 video shooting consists of lenses from Leica-R, Leica-M, Contax Zeiss, Nikon, Olympus OM, and even some c-mount bolex lenses. Hotrod Camera even makes a PL-mount lens mount for the GH1. No custom modification needed to use PL lenses.