The common condenses seems to be that GPA matters FAR more than degree for admissions into law school.
As a general rule of thumb, math, science and engineering programs are often thought to be more difficult to maintain a top GPA compared to 'softer' fields. This is not to say that one should not pursue such fields, but you should be aware that failing to maintain a strong GPA could seriously hurt your chances at admission to a top law school.
With this in mind, when choosing a tougher path through undergrad, select a field that you have a passion for. Hopefully this will provide you with the motivation necessary to stay on top of your coursework, helping to keep your GPA in a range that will give you a shot at the schools that you are interested in.