Depends. Do you want power locks/ windows, sunroof, fog lights, any other special features? If so then go for an LT,LTZ,Sport or anything higher than LS. If you don't care what options you get then the LS is for you. They are the base model cobalts. Same engines as the LT just not as good of options. They are always going to be the cheapest cobalts because of what limited specifications they have.
Having a fast honda is like coming out of the closet. you surprise everyone at first, but in the end your still gay.