In its second season, which begins tonight at 10, the show really begins to dig into emotional and social issues, from single motherhood and suburban morality to parenting in the modern world and the culture wars. In its first, very good season, it only scratched the surface of such things. There's a depth, a richness to the series now that was only suggested then.
I love this show, and enthusastically second the recommendation. The article has a recap of the first season, should you need it.