The main differences from a video standpoint between the 7D and the GF-1 are:
Canon 7D can do 1920 X 1080 @ 29.976, 25, or 23.976 fps, the GF-1 can only do 1280 x 720 at 60fps (which the canon can also do), so right there, the resolution is much higher and therefore better quality, and also offers more options for (arguably much more useful) frame rates.
The 7D captures h.264 video at a bitrate of approximately up to 50mbps. The GF-1 captures at only up to 17 mbps. The combination of this and the above mean higher quality video, but more stuttering on slower computers.
The GF-1 does not allow full manual exposure... only control over aperture and exposure compensation. The 7D allows you to control both the shutter speed and aperture, making it a much more usable creative video camera.
The sensor is larger on the 7D, which should give better DOF and lower light capabilities, even for video.
AVCHD may be more compatible with NLE's than raw h.264.. my understanding is that currently it takes a powerful computer to succesfully edit raw h.264 (especially from the 5d mark II) as well as a complicated workflow.
The GF-1 can also capture with Motion-Jpeg. More codec flexibility is good.
The lens selection for the 7D is much greater, making it a much more extensible system camera.
The 7D has a larger battery pack (1800 vs 1250 mah), which probably means that you can capture much more video off a single battery charge. You can also use a battery grip which can double the charge with the 7d, which does not seem possible with the GF1.
The GF-1 seems to have the ability to capture video clips up to the size of any compatible SD card. The 7D will limit the clip filesize to 4GB.
The GF-1 has continuous autofocus for video, albeit it only works well with certain lenses (the best of which only comes with a kit for the GH1). The 7d can only prefocus a shot, but cannot continually autofocus while recording.
Manual Focus on the GF-1 is fly-by-wire, meaning any focusing you do with the GF-1 will amount in some audible motor noise.
The GF-1 can only shoot with Mono Sound, with no option for an external mic or stereo of any sort (since the on board mic is mono). The 7d shoots with both stereo audio and also has the ability for an external mic so that audio can be capture off camera.
The GF-1 has a lower-res screen to check critical focus with, albeit it does have a faster frame rate.
The GF-1 can compose video with the optional EVF - the 7D can only compose with the 3" LCD or an external monitor - the OVF is closed down on live view activation.
I think that's pretty much it!
