Law A Level is more or less useless for a Law Degree. It's not in depth enough and you go straight back over it all again in the first few months of uni anyway, thats from the experiences of a few law students I know.
English Language isn't a patch on Literature, Literature is viewed as a better course (and it is), and is more interesting provided the teachers are good. English Literature also is a subject that is massively useful. It develops your ability to analyse, research, write and argue and put forth ideas and concepts. It's a reasonably hard course and varied over the 2 years of A Levels. I did it, enjoyed it, and did stuff as varied as comparsions of the dystopic novels 1984 and Brave New World, Blake, war literature and a bit of Shakespeare. Language is much more dry, of my 6th form friends who took it, few enjoyed it.
Ultimately though, at A Level, it's important to pick stuff you'll enjoy. It's much harder than what precedes it, and requires some form of conscious effort to do well. It's less about jumping through the hoops and memorising stuff, and more about thinking for yourself and really using what is taught to you. If you do a subject that you don't enjoy, you'll not succeed in it.
If you are going to go to uni, if you've got your eyes on anywhere decent, they hate media studies. And in psychology you'll spend a few lessons going over the delightful thing that is Penis Envy *giggles*.