Ethel's suggestions are good, particularly history for the reasons given by Sara3 and maths because of teh reasoning involved. I know History is well regarded by law schools. I'm not sure about law though- I've heard some universities prefer it if you haven't done law 'A' level. I think English and Phsycholgy are good too. But I still think you should do those academic subjects you enjoy because you'll do better in those- certainly don't do something you dislike just because the subject might look good on your CV.