I have made several and even though many people don't quilt them, I always do. I have found that I like the look of a quilted bag. It doesn't have to be alot, just some meandering or cross hatching. I think it makes the bag a bit sturdier. You will find which one you like better, quilted or not. They are so much fun to make and after you make your first one, you will see that the possibilities are endless.
Good Luck and Have fun!!!