Eric Alterman has two interesting analyses of The Sopranos from his correspondents. The first by Eric Rauchway last Thursday. The second by Ron Kampeas today. In both cases scroll down to find the Sopranos item.
Alterman himself adds this at the end of the Kampeas analysis:
I have always felt that Carmela is, morally speaking, the least defensible person on the series. Everyone else faces up to the consequences of their behavior to one degree or another. Only she considers herself pure, while sharing in the benefits of her ill-gotten gains.