From a longtime TPM reader ...

There are really only three polls out this morning (Susquehana released yesterday and was in the field only until April 10, before we got all "bitter"). The key measure here isn't the size of the lead, it's how they stack up to the previous polls taken by the same organizations last week. Of the three, one shows a slight tightening, one shows a widening by the same margin, and the third shows no change. None of these changes are statistically significant.

Survey USA:
Clinton 54 (-2), Obama 40 (+2)
Rasmussen:
Clinton 50 (+2), Obama 41 (-2)
Quinnipiac:
Clinton 50 (+0), Obama 44 (+0)

You wrote that "what each shows is Clinton halting Obama's advance and taking back some of her lead." In fact, I think that the data show the race remaining unchanged. Despite a media maelstorm, we're exactly where we were a week ago. Given the ferocity of the attacks and rebuttals, that's well worth noting.