...and although I'm not Christian I know more about the Bible than most Christians I know - I mean, I've actually read it!! *gasp!*
Anyway, my understanding (and take this as you will - I've never been a church-goer even though I was raised Christian (non-denominational), and it has been some time since the last time I read any of the Bible) is that Jesus died for our past sins, especially the unforgivable Original Sin. Jesus wiped the slate clean at that point, so we've effectively only been sinning for the last 2000 years instead of the last [insert length of human presence on earth as according to your beliefs].
Another interpretation/explanation I've heard was that Jesus died primarily to allow those who lived and died before him to get into heaven (because if you don't believe in Jesus as your lord and savior, you're going to Hell - but what happened to those who lived before him?).
Either way, though, Jesus died for past sins, not current ones, so you still need to avoid sinning and seek forgiveness when you do sin. If that's what you believe.
Anyway, my understanding (and take this as you will - I've never been a church-goer even though I was raised Christian (non-denominational), and it has been some time since the last time I read any of the Bible) is that Jesus died for our past sins, especially the unforgivable Original Sin. Jesus wiped the slate clean at that point, so we've effectively only been sinning for the last 2000 years instead of the last [insert length of human presence on earth as according to your beliefs].
Another interpretation/explanation I've heard was that Jesus died primarily to allow those who lived and died before him to get into heaven (because if you don't believe in Jesus as your lord and savior, you're going to Hell - but what happened to those who lived before him?).
Either way, though, Jesus died for past sins, not current ones, so you still need to avoid sinning and seek forgiveness when you do sin. If that's what you believe.