Hi Smiddy,
I'm not by any means an expert but there are a few different views on the significance of Christ Sacrifice on the cross. I've got it on my booklist to read Auelen's book on Christus Victor
You can read more on Wikipedia under the Christus Victor entry
Basically the three major ones are:
Ransom Theory - Satan holds everyone captive, Jesus pays the price for their release but being God, Satan has no hold on Him
Satisfaction Theory - (a.k.a Penal Substitution) which is commonly held in the western world. God's sense of justice for the sins of mankind must be satisfied for Him to relate to humanity. Jesus paid the price for the sins of all
Moral Influence view - Christ's death was the example of ultimate obedience.
The more I read about theology and church history, the more I find a richness of variety in thought. Which is really great because it provides so many alternatives to the black and white thinking that was instilled in me before..