I started out shooting 3:2 but then switched to 4:3 since (A) I shoot RAW and (B) I realized that I might as well get it all since I'm gonna crop and post process to my specs later anyway.
Interestingly, my post processing with the G1 has been very simple. I find for the most part it's only necessary to tweak the blacks or brightness. (Rarely, I may have to adjust the lighting temperature. But that's EXCEEDINGLY rare.)
In normal exposures I usually raise black level to about +16 from the default or to +22 or +32 on more backlit situations.
Brightness is kept at the default unless the shot's a little too under exposed where I want to bring out black backgrounds. Then I push the brightness from it's default to around +90 - +100 depending on the subject.
If I'm not satisfied with the sharpness (which is usually quite good with the kit lens and I am looking forward to the day when I can get an M adapter and use some of those lenses on the thing) I apply an unsharp mask at 45% (for women) and 80% for everyone else. (Not to be sexist or anything but when I'd applied the full 80% some ladies were a little upset with the detail that was revealed so I dialed it down and folks have been most pleased with the results.) At the most I will go to the default "auto sharpen".
On occasion I may adjust the lighting histogram if it calls for it (like in a winter scene). But, for the most part, I found with this camera that exposure has been spot on.
With BW images I convert at the RAW level (dialing down saturation) and adjust black and brightness accordingly.
If some minor blemish correction or horizon adjustment is required, after all has been done, then I use the necessary tools. But for the most part I prefer to work in 16 bit and keep that way as long as possible.
Then when all is said and done I create the various crops for individual files.
I shoot in ISO 100 to 400 as the noise according to what I've read is VERY low vs other cameras out there.
I'd be curious to know what others do as I'm always open for helpful suggestions.
P
By the way, the G1 has been simply awesome for portraits. With the articulating screen you can use it almost like a twin lens reflex keeping an eye on your subject and engaging him or her while shooting and insuring you're properly focused and framed.