Though most schools weight the numbers a little more; your LSAT score and GPA have a big impact, law school essays are definitely taken into account. Moreover, your law school essay will make or break your application if you're a borderline applicant, and it can even make up for a weak showing in the numbers department.
If you're applying to law school, your law school essay, along with your LSAT score and your undergraduate GPA, is going to be the most important factor in both what schools will accept you and how much scholarship money they're going to offer you.
Even if you're a huge long shot for a particular school the admissions staff will read at least the first paragraph of your law school essay, just to see what you have to offer. On the flipside, if you're a strong applicant to a particular school a bad law school essay can knock you out of the running if you're too flippant or stuck-up.
Though some law schools will give a required topic for your law school essay, most will offer up a few suggestions but allow you write on anything your heart desires. When writing your law school essay, avoid repeating any information that can be found on other parts of your application.
The admissions staff can read; they know what your GPA is and what activities you've taken part in. Instead, fill them in on what isn't on your application. Write on something that both defines who you are and why you stand out from the crowd.
Avoid over-used topics; writing about the most inspirational person you know or what difficulties you've overcome are tired topics and won't get you much attention unless it's something truly fresh or earth-shattering.
If the most inspirational person you know is the Unabomber or you were born without legs and can run a ten second fifty yard dash the admissions staff has probably heard it before.
The admissions staff has gone through thousands of applications, so tell them something about yourself that makes you stand out in their minds. Have you hiked the entire Appalachian Trail? Gone skydiving in a kayak? Raised your baby brother for a summer? Helped a poor family get a house?
Your activities don't necessarily have to be related to the law (though sometimes it helps), the topic you write about just needs to have been important to you. You should also have something to say about the topic, whatever it may be. Say it, and think of the law school essay as a way for the admissions staff to get to know you better.
