PPP polled the likely match-ups in the New Hampshire Senate race before the primary.
Public Policy Polling (PDF) 9/11-12 (7/23-25 results). MoE 2.2%
Kelly Ayotte (R) 47% (45)
Paul Hodes (D) 43% (42)
Not much change in the head-to-head from July, but check out Ayotte's favorables:
But while Ayotte had cast herself as a nonpartisan moderate, looking toward the general election, Lamontagne’s strong challenge from the right forced her to tout Sarah Palin’s endorsement in the primary, and her favorability rating has precipitously declined from 34-24 in April to 36-39 in July to 35-47 now. Though Ayotte has slightly strengthened her standing in the horse race with her own party’s voters and with unaffiliateds, 47% of Granite State voters think the Republican Party is too conservative, and by a 52-18 margin, they say they are less likely, rather than more likely, to vote for a Palin endorsee.
For most of the past year, commentators and many in the Democratic establishment have seemed to think Ayotte was invulnerable. But this is who she has always been -- an inexperienced candidate with significant negatives to exploit, more attractive as a generic than a reality. Someone whose favorables would decline from plus 10 to minus twelve between April and September in the course of a normally competitive primary campaign.
There's no guarantee Paul Hodes will effectively exploit that, but the Kelly Ayotte of September should not be seen as a surprise or a necessarily passing phenomenon. This is a pick-up Democrats have a chance at.
Update: In comments, Davidsfr points out this poll switches from a registered voter to likely voter model, which improves the picture further.