As others have said, original material helps you to stand out from the crowd of other wannabes, no matter how popular they may be.
Moreover, write with passion from your heart. If it doesn't interest you, don't write about it because likely it won't sound so exciting or convincing.
Which reminds me, I was once flying LIS to BCN, flipping through TAP's inflight magazine and reading some article in which the author claimed that you must breathe in order to write. Fascinating stuff!