Well, the fundamental question here is: what is a sin?
For me, its not clear-cut, not black/white. Eg lying: normally i dont agree with it, but there are tons of situation where imo it's better to ly than tell the truth. Or stealing: what if you steal to save a 1000 orphans from famine?
See, it's a grey area. This is off course a bit confusing, that's why some hardcore religious loons go back to the "source" and try to interpret everything literally. Just to avoid confusion, and not to think for themselves.
For me a true christian is somebody who helps his fellow man, who is positive and understanding. Too bad, a lot of the self-proclaimed "christians" are assholes, judgemental and dogmatic. Worst of all is when they are fundamentalists.
Also: religion is a PERSONAL matter, i hate it when they're claiming, god did this, god did that,.. God helped me win (so ... he helped the other one lose?). Keep your religion to yourself, unless you're being asked for it, plz.