If you are looking to practice your essay writing for the SAT, check out the lists of prompts from actual past tests (they say) on Alan Prep and on Magoosh.com.
Some examples from Alan Prep:
Should people make more of an effort to keep some things private?
Do people accomplish more when they are allowed to do things their own way?
Are we free to make our own decisions or are we limited in the choices we can make?
Would the world be a better place if everyone always told the complete truth?
Practicing essays is important. You need to get used to the limited time available, and you need to get used to thinking of concrete examples and developing your ideas. To properly prepare — for the SAT, and to prepare your mind to reason well (writing — good writing, that is — dramatically improves your ability to reason) — you should start training for the essay a few years before the test. Writing is not just for the SAT, it’s training in important aspects of reasoning and logic. Some good products to help with writing are those of the Institute for Excellence in Writing.