If I shoot video with my GL1 or GL2 in the 16:9 setting instead of 4:3, how is the quality of the video effected? Will it appear less sharp, more grainy, more pixilated, or will it have no effect on quality?
You GL2 will be better than the GL1 in widescreen mode because of the newer CCD's but you'll still lose some resolution because of the electronic 'stretch'. You need to shoot some footage and decide for yourself if it's going to be adequate for your needs. Comparatively, the in-camera widescreen mode of my Sony PD170 is awful when looking at the same widescreen footage shot with the GL2, even though the Sony has bigger CCD's than the Canon. Go figure.
I've never noticed any increase in picture noise between the two modes, just a drop in resolution. Your subject matter will also play a role in the quality of your widescreen footage. For example, a close up of someone's face will look better in widescreen mode than a shot of scenery or buildings with lots of high contrast detail, etc.
"I never knew the true meaning of happiness until I started shooting DV. But by then it was too late."