As I recall, after Reagan had used the line against Carter, Mondale was prepared for his "there you go again" and turned it right back on him, showing how Carter's accusation that he would propose cuts in Medicare were on the mark. I think Palin also tried it against Biden.
For my money, the best blow in these debates was the "I knew John Kennedy - you're no John Kennedy" line that Bentsen used against Quayle.
Of course Bentsen was ultimately on the losing side.
But the origin of the line is interesting. I heard in a course I'm taking that during debate rehearsal, the stand-in for Quayle (can't remember who this was) knew that Quayle liked to use the Kennedy comparison as one of his main claims to fame, so he pulled it out and hit Bentsen with it in a practice session.
Unaware that Quayle had used this in the past, Bentsen went ballistic, "What? Quayle actually makes this comparison? That's absurd! I knew Kennedy, he was a friend. Quayle is no Kennedy!" Immediately, so the story goes, Bentsen's handlers knew they had a winning line.
But somehow word leaked out to Quayle that they were going to pull this line out if he dared to use the Kennedy comparison.
Fast forward, during the debate, Quayle was asked what his qualifications were for the vice presidency. He had memorized 3 or so, and when asked again for more, having run out of canned responses, he dug down and all he could come up with was his similarity to Jack Kennedy. He took the chance and went for it.
Apparently, if you dig out the video, Bentsen can be seen smiling just as Quayle mentioned Kennedy, and confidently pulled out his "You're no Jack Kennedy," line.
Good story, not sure if it is true, but it sounds plausible.