Okay, a thread about songs where two singers are arguing with each other or at least having a disagreement. There's a couple more that come to mind but I'll start off with this one by Princess Chelsea (& Jonathan Bree)......The Cigarette Duet.
A Little Time - the Beautiful South Fairytale of New York - Pogues & Kirsty Macoll The Boy is Mine - Brandy & Monica A Christmas Duel - Hives & Cyndi Lauper
Here is an odd one. James Darren does a duet with himself (I think) on a bizarre Barry Mann/Cynthia Weil tune called "Conscience." It's not a line-by-line duet, but verse vs. chorus. The big "argument" comes at the close of each chorus. This single actually got to #11 and was a follow-up to his two big hits, "Goodbye Cruel World" and "Her Royal Majesty." To my ears, this single was an indirect precursor to the eccentric, post-"Pepper" pop that would hit the charts a few years later.
Surprised no one has posted The Girl Is Mine* yet. *(from Thriller, Michael Jackson argues with Paul McCartney. Obvious to most of us, but some might not know, right?)
Not sure whether this qualifies because one part is the first part of the song (sung) and the other part is the end of the song (spoken word), but She's Got Papers On Me by Richard "Dimples" Fields with Betty Wright doing the answer "rap" never fails to amuse me. For those unfamiliar, Richard laments that his wife won't let him go to be with the woman he really loves, and she responds by telling him to leave, but she's going to extract every cent she can from him on his way out. Betty's rap has so many funny lines, delivered so well by her, that sometimes I just play that part of the song.
"The Conference", by Nitin Sawhney, joined by Nikki Wells. You need to go forward to 11:45 for this, guarantee it's worth it (frankly so's the whole clip, but ain't nobody got that kinda time).