I use this bag more than any other. It's great for non-food shopping, as well as the regular trips to the grocery store.
Since I like it so much, and had more cotton-ease yarn, I decided to make another. This time I modified the pattern slightly to make a shorter bag. The first, though my favorite, really is longer than it needs to be for many shopping trips.
The diameter is only slightly smaller - 10 stitches, so I thought two shoulder straps would be better than one to reduce floppiness. I expect to get a lot of use out of this bag.
It is pictured with two rolls of paper towels in it. There was room for a third, but then it looked lumpy for the photo.
This side by side picture shows the difference in size between the two. The original pattern can be found here, at Knitty, a free online knitting magazine.