I don't do this often, but I thought that after hearing this message from Francis Chan at the 2010 Desiring God Conference, everyone should hear it. It's a powerful message, one that every Christian should hear and never forget because it's at the heart of the Gospel. Please take the hour or so to listen to this message and allow God to speak to you about how He's calling you to respond. Also, please don't stop at simply hearing it - be an effectual doer, as James put it. Let us all respond together so that the world may know God because of our love (John 13:35).
UPDATE: I was able to embed it below! Check it out - it's 68 minutes long, and worth every second: