I posted this to Lizzy. I hope the rest of you can get something from it.
About half of the department I work in is Mormon, My boss is even Mormon. I'm a member of a different protestant Christian religions (born and raised) and surprisingly enough interpret the bible and the basic call of morality in basically the same way that my Mormon friends do.
In talking with my friends at work it seems Mormons have some unpardonable sin categories. things that once done, or never done, or something, can result in a lesser heaven.
I for one, believe in only one God, only one heaven, and only one unpardonable (eternal) sin. That sin is turning your back on your savior. This sin can even be redeemed (read Job). thus leaving the only true unredeemable sin to be turning your back on God forever.
We are still called to uphold the law (exodus 20, the 10 commandmends) and to the new law of love (new testament theme) but it is the grace of God that frees us from our just punishment of death (The wages of sin is death), and through Jesus's death on the cross we are given the GIFT of eternal life. All we must do to be saved is ask. Thus explains how there is only one unpardonable sin.
Every person has their own believe. Most share their core belief with a group of believers (church or sect) but deep down every person does have their own individual belief.
I truly hope for you that you can be convinced of the saving grace of God so you don't have the feel the shame of leading a sinful life. No one on earth with the exception of one man (the perfect sacrafice, Jesus) has lead a perfect life. We are called to do the best we can, and through the sacrafice of Christ we are all made perfect.